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EtherealFrequently Asked Questions |
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EtherealFrequently Asked Questions |
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1.2 How much does Ethereal cost?
1.3 Can I use Ethereal commercially?
1.4 Can I use Ethereal as part of my commercial product?
1.5 What protocols are currently supported?
1.6 Are there any plans to support {your favorite protocol}?
1.7 Can Ethereal read capture files from {your favorite network analyzer}?
1.8 What devices can Ethereal use to capture packets?
1.9 How do you pronounce Ethereal? Where did the name come from?
2.2 When I try to download the WinPcap driver and library, I can't get to the WinPcap Web site.
4.3 The link fails with a number of "Output line too long." messages followed by linker errors.
4.4 The link fails on Solaris because plugin_list is undefined.
4.5 The build fails on Windows because of conflicts between winsock.h and winsock2.h.
5.3 I'm only seeing ARP packets when I try to capture traffic.
5.9 Can Ethereal capture on (my T1/E1 line, SS7 links, etc.)?
5.10 How do I put an interface into promiscuous mode?
5.11 I can set a display filter just fine, but capture filters don't work.
5.12 I'm entering valid capture filters, but I still get "parse error" errors.
5.14 Why am I seeing lots of packets with incorrect TCP checksums?
5.15 I've just installed Ethereal, and the traffic on my local LAN is boring.
5.16 When I run Ethereal on Solaris 8, it dies with a Bus Error when I start it.
5.20 When I try to run Ethereal, it complains about sprint_realloc_objid being undefined.
5.23 When I try to run Ethereal on Windows, it fails to run because it can't find packet.dll.
5.27 I'm trying to capture traffic but I'm not seeing any.
5.30 Does Ethereal work on Windows Me?
5.31 Does Ethereal work on Windows XP?
5.32 Why doesn't Ethereal correctly identify RTP packets? It shows them only as UDP.
5.37 How can I capture raw 802.11 frames, including non-data (management, beacon) frames?
5.38 How do I capture on an 802.11 device in monitor mode?
5.39 I'm trying to capture 802.11 traffic on Windows; why am I not seeing any packets?
5.41 How can I capture packets with CRC errors?
5.42 How can I capture entire frames, including the FCS?
5.43 Why does Ethereal hang after I stop a capture?
5.44 How can I search for, or filter, packets that have a particular string anywhere in them?
5.45 How do I filter a capture to see traffic for virus XXX?
Q 1.1: Where can I get help?
A: Community support is available on the ethereal-users mailing list. Subscription information and archives for all of Ethereal's mailing lists can be found at http://www.ethereal.com/lists. An IRC channel dedicated to Ethereal can be found at irc://irc.freenode.net/ethereal.
Commercial support, training, and development services are available from Ethereal Software.
Q 1.2: How much does Ethereal cost?
A: Ethereal is "free software"; you can download it without paying any license fee. The version of Ethereal you download isn't a "demo" version, with limitations not present in a "full" version; it is the full version.
The license under which Ethereal is issued is the GNU General Public License. See the GNU GPL FAQ for some more information.
Q 1.3: Can I use Ethereal commercially?
A: Yes, if, for example, you mean "I work for a commercial organization; can I use Ethereal to capture and analyze network traffic in our company's networks or in our customer's networks?"
If you mean "Can I use Ethereal as part of my commercial product?", see the next entry in the FAQ.
Q 1.4: Can I use Ethereal as part of my commercial product?
A: As noted, Ethereal is licensed under the GNU General Public License. The GPL imposes conditions on your use of GPL'ed code in your own products; you cannot, for example, make a "derived work" from Ethereal, by making modifications to it, and then sell the resulting derived work and not allow recipients to give away the resulting work. You must also make the changes you've made to the Ethereal source available to all recipients of your modified version; those changes must also be licensed under the terms of the GPL. See the GPL FAQ for more details; in particular, note the answer to the question about modifying a GPLed program and selling it commercially, and the question about linking GPLed code with other code to make a proprietary program.
You can combine a GPLed program such as Ethereal and a commercial program as long as they communicate "at arm's length", as per this item in the GPL FAQ.
Q 1.5: What protocols are currently supported?
A: There are currently 724 supported protocols and media, listed below. Descriptions can be found in the ethereal(1) man page.
3Com XNS Encapsulation
3GPP2 A11
802.1Q Virtual LAN
802.1X Authentication
AAL type 2 signalling protocol - Capability set 1 (Q.2630.1)
ACN
ACSE
AFS (4.0) Replication Server call declarations
AIM Administrative
AIM Advertisements
AIM Buddylist Service
AIM Chat Navigation
AIM Chat Service
AIM Directory Search
AIM E-mail
AIM Generic Service
AIM ICQ
AIM Invitation Service
AIM Location
AIM Messaging
AIM OFT
AIM Popup
AIM Privacy Management Service
AIM Server Side Info
AIM Server Side Themes
AIM Signon
AIM Statistics
AIM Translate
AIM User Lookup
ANSI A-I/F BSMAP
ANSI A-I/F DTAP
ANSI IS-637-A (SMS) Teleservice Layer
ANSI IS-637-A (SMS) Transport Layer
ANSI IS-683-A (OTA (Mobile))
ANSI IS-801 (Location Services (PLD))
ANSI Mobile Application Part
AOL Instant Messenger
ARCNET
ASN.1 decoding
ATAoverEthernet
ATM
ATM AAL1
ATM AAL3/4
ATM LAN Emulation
ATM OAM AAL
AVS WLAN Capture header
AX/4000 Test Block
Active Directory Setup
Ad hoc On-demand Distance Vector Routing Protocol
Adaptive Multi-Rate
Address Resolution Protocol
AgentX
Aggregate Server Access Protocol
Alert Standard Forum
Alteon - Transparent Proxy Cache Protocol
Andrew File System (AFS)
Apache JServ Protocol v1.3
Apple Filing Protocol
Apple IP-over-IEEE 1394
AppleTalk Session Protocol
AppleTalk Transaction Protocol packet
Appletalk Address Resolution Protocol
Application Configuration Access Protocol
Art-Net
Aruba - Aruba Discovery Protocol
Async data over ISDN (V.120)
Asynchronous Layered Coding
AudioCodes Trunk Trace
Authentication Header
BACnet Virtual Link Control
BEA Tuxedo
BSSAP/BSAP
Banyan Vines ARP
Banyan Vines Echo
Banyan Vines Fragmentation Protocol
Banyan Vines ICP
Banyan Vines IP
Banyan Vines IPC
Banyan Vines LLC
Banyan Vines RTP
Banyan Vines SPP
Base Station Subsystem GPRS Protocol
Basic Encoding Rules (ASN.1 X.690)
Bearer Independent Call Control
Bi-directional Fault Detection Control Message
BitTorrent
Blocks Extensible Exchange Protocol
Blubster/Piolet MANOLITO Protocol
Boardwalk
Boot Parameters
Bootstrap Protocol
Border Gateway Protocol
Building Automation and Control Network APDU
Building Automation and Control Network NPDU
CBAPhysicalDevice
CCSDS
CDS Clerk Server Calls
CSM_ENCAPS
Camel
Cast Client Control Protocol
Certificate Management Protocol
Certificate Request Message Format
Check Point High Availability Protocol
Checkpoint FW-1
Cisco Auto-RP
Cisco Discovery Protocol
Cisco Group Management Protocol
Cisco HDLC
Cisco Hot Standby Router Protocol
Cisco ISL
Cisco Interior Gateway Routing Protocol
Cisco NetFlow
Cisco SLARP
Cisco Session Management
Cisco Wireless Layer 2
Clearcase NFS
CoSine IPNOS L2 debug output
Common Industrial Protocol
Common Open Policy Service
Common Unix Printing System (CUPS) Browsing Protocol
Compuserve GIF
Computer Interface to Message Distribution
Configuration Test Protocol (loopback)
Connectionless Lightweight Directory Access Protocol
Coseventcomm Dissector Using GIOP API
Cosnaming Dissector Using GIOP API
Cross Point Frame Injector
Cryptographic Message Syntax
DCE Distributed Time Service Local Server
DCE Distributed Time Service Provider
DCE Name Service
DCE RPC
DCE Security ID Mapper
DCE/DFS BUDB
DCE/RPC BOS Server
DCE/RPC BUTC
DCE/RPC CDS Solicitation
DCE/RPC Conversation Manager
DCE/RPC Directory Acl Interface
DCE/RPC Endpoint Mapper
DCE/RPC Endpoint Mapper v4
DCE/RPC FLDB
DCE/RPC FLDB UBIK TRANSFER
DCE/RPC FLDB UBIKVOTE
DCE/RPC ICL RPC
DCE/RPC Kerberos V
DCE/RPC NCS 1.5.1 Local Location Broker
DCE/RPC Operations between registry server replicas
DCE/RPC Prop Attr
DCE/RPC RS_ACCT
DCE/RPC RS_BIND
DCE/RPC RS_MISC
DCE/RPC RS_PROP_ACCT
DCE/RPC RS_UNIX
DCE/RPC Registry Password Management
DCE/RPC Registry Server Attributes Schema
DCE/RPC Registry server propagation interface - ACLs.
DCE/RPC Registry server propagation interface - PGO items
DCE/RPC Registry server propagation interface - properties and policies
DCE/RPC Remote Management
DCE/RPC Repserver Calls
DCE/RPC TokenServer Calls
DCE/RPC UpServer
DCOM
DCOM IDispatch
DCOM IRemoteActivation
DCOM OXID Resolver
DEC DNA Routing Protocol
DEC Spanning Tree Protocol
DFS Calls
DG Gryphon Protocol
DHCP Failover
DHCPv6
DICOM
DLT_USER_A
DLT_USER_B
DLT_USER_C
DLT_USER_D
DNS Control Program Server
DOCSIS 1.1
DOCSIS Appendix C TLV's
DOCSIS Baseline Privacy Key Management Attributes
DOCSIS Baseline Privacy Key Management Request
DOCSIS Baseline Privacy Key Management Response
DOCSIS Dynamic Service Addition Acknowledge
DOCSIS Dynamic Service Addition Request
DOCSIS Dynamic Service Addition Response
DOCSIS Dynamic Service Change Acknowledgement
DOCSIS Dynamic Service Change Request
DOCSIS Dynamic Service Change Response
DOCSIS Dynamic Service Delete Request
DOCSIS Dynamic Service Delete Response
DOCSIS Initial Ranging Message
DOCSIS Mac Management
DOCSIS Range Request Message
DOCSIS Ranging Response
DOCSIS Registration Acknowledge
DOCSIS Registration Requests
DOCSIS Registration Responses
DOCSIS Upstream Bandwidth Allocation
DOCSIS Upstream Channel Change Request
DOCSIS Upstream Channel Change Response
DOCSIS Upstream Channel Descriptor
DOCSIS Upstream Channel Descriptor Type 29
DOCSIS Vendor Specific Endodings
DPNSS/DASS2-User Adaptation Layer
DRSUAPI
Data
Data Link SWitching
Data Stream Interface
Datagram Congestion Control Protocol
Datagram Delivery Protocol
Decompressed SigComp message as raw text
Diameter Protocol
Digital Audio Access Protocol
Distance Vector Multicast Routing Protocol
Distcc Distributed Compiler
Distributed Checksum Clearinghouse Protocol
Distributed Interactive Simulation
Distributed Network Protocol 3.0
Domain Name Service
Dublin Core Metadata (DC)
Dynamic DNS Tools Protocol
Dynamic Trunking Protocol
ENTTEC
Echo
Encapsulating Security Payload
Endpoint Name Resolution Protocol
Enhanced Interior Gateway Routing Protocol
EtherNet/IP (Industrial Protocol)
Etheric
Ethernet
Ethernet over IP
Extended Security Services
Extensible Authentication Protocol
Extreme Discovery Protocol
FC Extended Link Svc
FC Fabric Configuration Server
FCIP
FTP Data
FTServer Operations
Fiber Distributed Data Interface
Fibre Channel
Fibre Channel Common Transport
Fibre Channel Fabric Zone Server
Fibre Channel Name Server
Fibre Channel Protocol for SCSI
Fibre Channel SW_ILS
Fibre Channel Security Protocol
Fibre Channel Single Byte Command
File Transfer Protocol (FTP)
Financial Information eXchange Protocol
Frame
Frame Relay
G.723
GARP Multicast Registration Protocol
GARP VLAN Registration Protocol
GPRS Network service
GPRS Tunneling Protocol
GSM A-I/F BSSMAP
GSM A-I/F DTAP
GSM A-I/F RP
GSM Mobile Application
GSM SMS TPDU (GSM 03.40)
GSM Short Message Service User Data
GSM_SS
GSS-API Generic Security Service Application Program Interface
General Inter-ORB Protocol
Generic Routing Encapsulation
Gnutella Protocol
H.248 MEGACO
H221NonStandard
H235-SECURITY-MESSAGES
H323-MESSAGES
HP Extended Local-Link Control
HP Remote Maintenance Protocol
HP Switch Protocol
HP-UX Network Tracing and Logging
Hummingbird NFS Daemon
HyperSCSI
Hypertext Transfer Protocol
ICBAAccoCallback
ICBAAccoCallback2
ICBAAccoMgt
ICBAAccoMgt2
ICBAAccoServer
ICBAAccoServer2
ICBAAccoServerSRT
ICBAAccoSync
ICBABrowse
ICBABrowse2
ICBAGroupError
ICBAGroupErrorEvent
ICBALogicalDevice
ICBALogicalDevice2
ICBAPersist
ICBAPersist2
ICBAPhysicalDevice
ICBAPhysicalDevice2
ICBAPhysicalDevicePC
ICBAPhysicalDevicePCEvent
ICBARTAuto
ICBARTAuto2
ICBAState
ICBAStateEvent
ICBASystemProperties
ICBATime
ICQ Protocol
IEEE 802.11 Radiotap Capture header
IEEE 802.11 wireless LAN
IEEE 802.11 wireless LAN management frame
IEEE802a OUI Extended Ethertype
ILMI
INAP
IP Device Control (SS7 over IP)
IP Over FC
IP Payload Compression
IP Virtual Services Sync Daemon
IPX Message
IPX Routing Information Protocol
IPX WAN
IRemUnknown
IRemUnknown2
ISDN
ISDN Q.921-User Adaptation Layer
ISDN User Part
ISO 10589 ISIS InTRA Domain Routeing Information Exchange Protocol
ISO 8073 COTP Connection-Oriented Transport Protocol
ISO 8327-1 OSI Session Protocol
ISO 8473 CLNP ConnectionLess Network Protocol
ISO 8571 FTAM
ISO 8602 CLTP ConnectionLess Transport Protocol
ISO 8823 OSI Presentation Protocol
ISO 9542 ESIS Routeing Information Exchange Protocol
ISUP Thin Protocol
ISystemActivator ISystemActivator Resolver
ITU M.3100 Generic Network Information Model
ITU-T E.164 number
ITU-T Recommendation H.261
ITU-T Recommendation H.263
ITU-T Recommendation H.263 RTP Payload header (RFC2190)
InMon sFlow
Information Access Protocol
Init shutdown service
Intel ANS probe
Intelligent Platform Management Interface
Inter-Access-Point Protocol
Inter-Asterisk eXchange v2
InterSwitch Message Protocol
Interbase
Internet Cache Protocol
Internet Communications Engine Protocol
Internet Content Adaptation Protocol
Internet Control Message Protocol
Internet Control Message Protocol v6
Internet Group Management Protocol
Internet Group membership Authentication Protocol
Internet Message Access Protocol
Internet Printing Protocol
Internet Protocol
Internet Protocol Version 6
Internet Relay Chat
Internet Security Association and Key Management Protocol
Internetwork Datagram Protocol
Internetwork Packet eXchange
IrCOMM Protocol
IrDA Link Access Protocol
IrDA Link Management Protocol
JPEG File Interchange Format
JXTA Connection Welcome Message
JXTA Message
JXTA Message Framing
JXTA P2P
JXTA UDP
Jabber XML Messaging
Java RMI
Java Serialization
Juniper
K12xx
Kerberized Internet Negotiation of Key
Kerberos
Kerberos Administration
Kerberos v4
Kernel Lock Manager
LWAP Control Message
LWAPP Encapsulated Packet
LWAPP Layer 3 Packet
Label Distribution Protocol
Laplink
Layer 2 Tunneling Protocol
Light Weight DNS RESolver (BIND9)
Lightweight Directory Access Protocol
Line Printer Daemon Protocol
Line-based text data
Link Access Procedure Balanced (LAPB)
Link Access Procedure Balanced Ethernet (LAPBETHER)
Link Access Procedure, Channel D (LAPD)
Link Layer Discovery Protocol
Link Management Protocol (LMP)
Linux cooked-mode capture
Local Management Interface
LocalTalk Link Access Protocol
Log Message
Logical Link Control GPRS
Logical-Link Control
Logotype Certificate Extensions
Lucent/Ascend debug output
MAC Control
MAP_DialoguePDU
MDS Header
MEGACO
MIME Multipart Media Encapsulation
MMS
MMS Message Encapsulation
MS Kpasswd
MS Proxy Protocol
MSN Messenger Service
MSNIP: Multicast Source Notification of Interest Protocol
MTP 2 Transparent Proxy
MTP 2 User Adaptation Layer
MTP 3 User Adaptation Layer
MTP2 Peer Adaptation Layer
MULTIMEDIA-SYSTEM-CONTROL
Media Gateway Control Protocol
Media Type
Media Type: message/http
Message Session Relay Protocol
Message Transfer Part Level 2
Message Transfer Part Level 3
Message Transfer Part Level 3 Management
Meta Analysis Tracing Engine
Microsoft AT-Scheduler Service
Microsoft Distributed File System
Microsoft Distributed Link Tracking Server Service
Microsoft Encrypted File System Service
Microsoft Eventlog Service
Microsoft Exchange MAPI
Microsoft File Replication Service
Microsoft File Replication Service API
Microsoft Local Security Architecture
Microsoft Media Server
Microsoft Messenger Service
Microsoft Network Logon
Microsoft Plug and Play service
Microsoft Routing and Remote Access Service
Microsoft Security Account Manager
Microsoft Server Service
Microsoft Service Control
Microsoft Spool Subsystem
Microsoft Telephony API Service
Microsoft Windows Browser Protocol
Microsoft Windows Lanman Remote API Protocol
Microsoft Windows Logon Protocol (Old)
Microsoft Workstation Service
Mobile IP
Mobile IPv6
Modbus/TCP
Monotone Netsync
Mount Service
MultiProtocol Label Switching Header
Multicast Router DISCovery protocol
Multicast Source Discovery Protocol
Multiprotocol Label Switching Echo
MySQL Protocol
NFSACL
NFSAUTH
NIS+
NIS+ Callback
NSPI
NTLM Secure Service Provider
Name Binding Protocol
Name Management Protocol over IPX
Negative-acknowledgment Oriented Reliable Multicast
NetBIOS
NetBIOS Datagram Service
NetBIOS Name Service
NetBIOS Session Service
NetBIOS over IPX
NetScape Certificate Extensions
NetWare Core Protocol
NetWare Link Services Protocol
NetWare Serialization Protocol
Network Data Management Protocol
Network File System
Network Lock Manager Protocol
Network News Transfer Protocol
Network Service Over IP
Network Status Monitor CallBack Protocol
Network Status Monitor Protocol
Network Time Protocol
Nortel SONMP
Novell Distributed Print System
Novell Modular Authentication Service
Null/Loopback
Online Certificate Status Protocol
Open Policy Service Interface
Open Shortest Path First
OpenBSD Encapsulating device
OpenBSD Packet Filter log file
OpenBSD Packet Filter log file, pre 3.4
Optimized Link State Routing Protocol
PC NFS
PKCS#1
PKINIT
PKIX CERT File Format
PKIX Qualified
PKIX Time Stamp Protocol
PKIX1Explitit
PKIX1Implitit
PKIXProxy (RFC3820)
PPP Bandwidth Allocation Control Protocol
PPP Bandwidth Allocation Protocol
PPP CDP Control Protocol
PPP Callback Control Protocol
PPP Challenge Handshake Authentication Protocol
PPP Compressed Datagram
PPP Compression Control Protocol
PPP IP Control Protocol
PPP IPv6 Control Protocol
PPP In HDLC-Like Framing
PPP Link Control Protocol
PPP MPLS Control Protocol
PPP Multilink Protocol
PPP Multiplexing
PPP OSI Control Protocol
PPP Password Authentication Protocol
PPP VJ Compression
PPP-over-Ethernet Discovery
PPP-over-Ethernet Session
PPPMux Control Protocol
PROFINET DCP
PROFINET IO
PROFINET Real-Time Protocol
Packed Encoding Rules (ASN.1 X.691)
Packet Cable Lawful Intercept
PacketCable
Parlay Dissector Using GIOP API
Plan 9 9P
Point-to-Point Protocol
Point-to-Point Tunnelling Protocol
Port Aggregation Protocol
Portmap
Post Office Protocol
PostgreSQL
Pragmatic General Multicast
Precision Time Protocol (IEEE1588)
Prism
Privilege Server operations
Protocol Independent Multicast
Q.2931
Q.931
Q.933
Quake II Network Protocol
Quake III Arena Network Protocol
Quake Network Protocol
QuakeWorld Network Protocol
Qualified Logical Link Control
RDM
RFC 2250 MPEG1
RFC 2833 RTP Event
RIPng
RPC Browser
RS Interface properties
RSTAT
RSYNC File Synchroniser
RTcfg
RX Protocol
Radio Access Network Application Part
Radius Protocol
Raw packet data
Real Data Transport
Real Time Streaming Protocol
Real-Time Media Access Control
Real-Time Publish-Subscribe Wire Protocol
Real-Time Transport Protocol
Real-time Transport Control Protocol
Redback
Redundant Link Management Protocol
Registry Server Attributes Manipulation Interface
Registry server administration operations.
Reliable UDP
Remote Management Control Protocol
Remote Override interface
Remote Procedure Call
Remote Program Load
Remote Quota
Remote Registry Service
Remote Shell
Remote Wall protocol
Remote sec_login preauth interface.
Resource ReserVation Protocol (RSVP)
Retix Spanning Tree Protocol
Rlogin Protocol
Routing Information Protocol
Routing Table Maintenance Protocol
SADMIND
SCSI
SEBEK - Kernel Data Capture
SGI Mount Service
SMB (Server Message Block Protocol)
SMB MailSlot Protocol
SMB Pipe Protocol
SNA-over-Ethernet
SNMP Multiplex Protocol
SPNEGO-KRB5
SPRAY
SS7 SCCP-User Adaptation Layer
SSCF-NNI
SSCOP
SSH Protocol
STANAG 4406 Military Message Extensions
Secure Socket Layer
Sequenced Packet Protocol
Sequenced Packet eXchange
Serial Infrared
Service Advertisement Protocol
Service Location Protocol
Session Announcement Protocol
Session Description Protocol
Session Initiation Protocol
Session Initiation Protocol (SIP as raw text)
Short Message Peer to Peer
Short Message Relaying Service
Signaling Compression
Signalling Connection Control Part
Signalling Connection Control Part Management
Simple Mail Transfer Protocol
Simple Network Management Protocol
Simple Protected Negotiation
Simple Traversal of UDP Through NAT
Sinec H1 Protocol
Sipfrag
Skinny Client Control Protocol
SliMP3 Communication Protocol
Slow Protocols
Socks Protocol
SoulSeek Protocol
Spanning Tree Protocol
Stream Control Transmission Protocol
Subnetwork Dependent Convergence Protocol
Symantec Enterprise Firewall
Synchronized Multimedia Integration Language
Synchronous Data Link Control (SDLC)
Synergy
Syslog message
Systems Network Architecture
Systems Network Architecture XID
T.38
TACACS
TACACS+
TDMA RTmac Discipline
TEI Management Procedure, Channel D (LAPD)
TPKT - ISO on TCP - RFC1006
Tabular Data Stream
Tango Dissector Using GIOP API
Tazmen Sniffer Protocol
Telnet
Teredo IPv6 over UDP tunneling
The Armagetron Advanced OpenGL Tron clone
Time Protocol
Time Synchronization Protocol
Tiny Transport Protocol
Token-Ring
Token-Ring Media Access Control
Transaction Capabilities Application Part
Transmission Control Protocol
Transparent Network Substrate Protocol
Transport Adapter Layer Interface v1.0, RFC 3094
Trivial File Transfer Protocol
UDP Encapsulation of IPsec Packets
Universal Computer Protocol
Unlicensed Mobile Access
User Datagram Protocol
V5.2-User Adaptation Layer
Virtual Network Computing
Virtual Router Redundancy Protocol
Virtual Trunking Protocol
WAP Binary XML
WAP Session Initiation Request
WINS (Windows Internet Name Service) Replication
Web Cache Coordination Protocol
WebSphere MQ
WebSphere MQ Programmable Command Formats
Wellfleet Breath of Life
Wellfleet Compression
Wellfleet HDLC
Who
Windows 2000 DNS
Wireless Session Protocol
Wireless Transaction Protocol
Wireless Transport Layer Security
Wlan Certificate Extension
X Display Manager Control Protocol
X.228 OSI Reliable Transfer Service
X.25
X.25 over TCP
X.29
X.411 OSI Message Transfer Service
X.420 OSI Information Object
X.509 Authentication Framework
X.509 Certificate Extensions
X.509 Information Framework
X.509 Selected Attribute Types
X.880 OSI Remote Operations Service
X11
X711 CMIP
Xyplex
Yahoo Messenger Protocol
Yahoo YMSG Messenger Protocol
Yellow Pages Bind
Yellow Pages Passwd
Yellow Pages Service
Yellow Pages Transfer
Zebra Protocol
Zone Information Protocol
eDonkey Protocol
eXtensible Markup Language
giFT Internet File Transfer
h450
iFCP
iSCSI
iSNS
iTunes podCast rss elements
rss
Q 1.6: Are there any plans to support {your favorite protocol}?
A: Support for particular protocols is added to Ethereal as a result of people contributing that support; no formal plans for adding support for particular protocols in particular future releases exist.
Q 1.7: Can Ethereal read capture files from {your favorite network analyzer}?
A: Support for particular protocols is added to Ethereal as a result of people contributing that support; no formal plans for adding support for particular protocols in particular future releases exist.
If a network analyzer writes out files in a format already supported by Ethereal (e.g., in libpcap format), Ethereal may already be able to read them, unless the analyzer has added its own proprietary extensions to that format.
If a network analyzer writes out files in its own format, or has added proprietary extensions to another format, in order to make Ethereal read captures from that network analyzer, we would either have to have a specification for the file format, or the extensions, sufficient to give us enough information to read the parts of the file relevant to Ethereal, or would need at least one capture file in that format AND a detailed textual analysis of the packets in that capture file (showing packet time stamps, packet lengths, and the top-level packet header) in order to reverse-engineer the file format.
Note that there is no guarantee that we will be able to reverse-engineer a capture file format.
Q 1.8: What devices can Ethereal use to capture packets?
A: Ethereal can read live data from Ethernet, Token-Ring, FDDI, serial (PPP and SLIP) (if the OS on which it's running allows Ethereal to do so), 802.11 wireless LAN (if the OS on which it's running allows Ethereal to do so), ATM connections (if the OS on which it's running allows Ethereal to do so), and the "any" device supported on Linux by recent versions of libpcap. See the list of supported capture media on various OSes for details (several items in there say "Unknown", which doesn't mean "Ethereal can't capture on them", it means "we don't know whether it can capture on them"; we expect that it will be able to capture on many of them, but we haven't tried it ourselves - if you try one of those types and it works, please send an update to ethereal-web[AT]ethereal.com ).
It can also read a variety of capture file formats, including:
so that it can read traces from various network types, as captured by other applications or equipment, even if it cannot itself capture on those network types.
Q 1.9: How do you pronounce Ethereal? Where did the name come from?
A: The English pronunciation can be found in Merriam-Webster's online dictionary at http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&va=ethereal.
According to the book "Computer Networks" by Andrew Tannenbaum, Ethernet was named after the "luminiferous ether" which was once thought to carry electromagnetic radiation. Taking that into consideration, Ethereal seemed like an appropriate name for something that started out as an Ethernet analyzer.
Q 2.1: I downloaded the Win32 installer, but when I try to run it, I get an error.
A: The program you used to download it may have downloaded it incorrectly. Web browsers sometimes may do this.
Try downloading it with, for example:
If you use the ftp command, make sure you do the transfer in binary mode rather than ASCII mode, by using the binary command before transferring the file.
Q 2.2: When I try to download the WinPcap driver and library, I can't get to the WinPcap Web site.
A: As is the case with all Web sites, that site won't necessarily always be accessible; the server may be down due to a problem or down for maintenance, or there may be a networking problem between you and the server. You should try again later, or try the local mirror or the Wiretapped.net mirror.
Q 3.1: I installed an Ethereal RPM, but Ethereal doesn't seem to be installed; only Tethereal is installed.
A: Older versions of the Red Hat RPMs for Ethereal put only the non-GUI components into the ethereal RPM, the fact that Ethereal is a GUI program nonwithstanding; newer versions make it a bit clearer by giving that RPM a name starting with ethereal-base.
In those older versions, there's a separate ethereal-gnome RPM that includes GUI components such as Ethereal itself, the fact that Ethereal doesn't use GNOME nonwithstanding; newer versions make it a bit clearer by giving that RPM a name starting with ethereal-gtk+.
Find the ethereal-gnome or ethereal-gtk+ RPM, and install that also.
Q 4.1: The configure script can't find pcap.h or bpf.h, but I have libpcap installed.
A: Are you sure pcap.h and bpf.h are installed? The official distribution of libpcap only installs the libpcap.a library file when "make install" is run. To install pcap.h and bpf.h, you must run "make install-incl". If you're running Debian or Redhat, make sure you have the "libpcap-dev" or "libpcap-devel" packages installed.
It's also possible that pcap.h and bpf.h have been installed in a strange location. If this is the case, you may have to tweak aclocal.m4.
Q 4.2:
Why do I get the error
dftest_DEPENDENCIES was already defined in condition TRUE,
which implies condition HAVE_PLUGINS_TRUE
when I try to build Ethereal from SVN or a SVN snapshot?
A: You probably have automake 1.5 installed on your machine (the command automake --version will report the version of automake on your machine). There is a bug in that version of automake that causes this problem; upgrade to a later version of automake (1.6 or later).
Q 4.3: The link fails with a number of "Output line too long." messages followed by linker errors.
A: The version of the sed command on your system is incapable of handling very long lines. On Solaris, for example, /usr/bin/sed has a line length limit too low to allow libtool to work; /usr/xpg4/bin/sed can handle it, as can GNU sed if you have it installed.
On Solaris, changing your command search path to search /usr/xpg4/bin before /usr/bin should make the problem go away; on any platform on which you have this problem, installing GNU sed and changing your command path to search the directory in which it is installed before searching the directory with the version of sed that came with the OS should make the problem go away.
Q 4.4: The link fails on Solaris because plugin_list is undefined.
A: This appears to be due to a problem with some versions of the GTK+ and GLib packages from www.sunfreeware.org; un-install those packages, and try getting the 1.2.10 versions from that site, or the versions from The Written Word, or the versions from Sun's GNOME distribution, or the versions from the supplemental software CD that comes with the Solaris media kit, or build them from source from the GTK Web site. Then re-run the configuration script, and try rebuilding Ethereal. (If you get the 1.2.10 versions from www.sunfreeware.org, and the problem persists, un-install them and try installing one of the other versions mentioned.)
Q 4.5: The build fails on Windows because of conflicts between winsock.h and winsock2.h.
A: As of Ethereal 0.9.5, you must install WinPcap 2.3 or later, and the corresponding version of the developer's pack, in order to be able to compile Ethereal; it will not compile with older versions of the developer's pack. The symptoms of this failure are conflicts between definitions in winsock.h and in winsock2.h; Ethereal uses winsock2.h, but pre-2.3 versions of the WinPcap developer's packet use winsock.h. (2.3 uses winsock2.h, so if Ethereal were to use winsock.h, it would not be able to build with current versions of the WinPcap developer's pack.)
Note that the installed version of the developer's pack should be the same version as the version of WinPcap you have installed.
Q 5.1: When I use Ethereal to capture packets, I see only packets to and from my machine, or I'm not seeing all the traffic I'm expecting to see from or to the machine I'm trying to monitor.
A: This might be because the interface on which you're capturing is plugged into an Ethernet or Token Ring switch; on a switched network, unicast traffic between two ports will not necessarily appear on other ports - only broadcast and multicast traffic will be sent to all ports.
Note that even if your machine is plugged into a hub, the "hub" may be a switched hub, in which case you're still on a switched network.
Note also that on the Linksys Web site, they say that their auto-sensing hubs "broadcast the 10Mb packets to the port that operate at 10Mb only and broadcast the 100Mb packets to the ports that operate at 100Mb only", which would indicate that if you sniff on a 10Mb port, you will not see traffic coming sent to a 100Mb port, and vice versa. This problem has also been reported for Netgear dual-speed hubs, and may exist for other "auto-sensing" or "dual-speed" hubs.
Some switches have the ability to replicate all traffic on all ports to a single port so that you can plug your analyzer into that single port to sniff all traffic. You would have to check the documentation for the switch to see if this is possible and, if so, to see how to do this. See the switch reference page on the Ethereal Wiki for information on some switches. (Note that it's a Wiki, so you can update or fix that information, or add additional information on those switches or information on new switches, yourself.)
Note also that many firewall/NAT boxes have a switch built into them; this includes many of the "cable/DSL router" boxes. If you have a box of that sort, that has a switch with some number of Ethernet ports into which you plug machines on your network, and another Ethernet port used to connect to a cable or DSL modem, you can, at least, sniff traffic between the machines on your network and the Internet by plugging the Ethernet port on the router going to the modem, the Ethernet port on the modem, and the machine on which you're running Ethereal into a hub (make sure it's not a switching hub, and that, if it's a dual-speed hub, all three of those ports are running at the same speed.
If your machine is not plugged into a switched network or a dual-speed hub, or it is plugged into a switched network but the port is set up to have all traffic replicated to it, the problem might be that the network interface on which you're capturing doesn't support "promiscuous" mode, or because your OS can't put the interface into promiscuous mode. Normally, network interfaces supply to the host only:
If the interface is not running in promiscuous mode, it won't see any traffic that isn't intended to be seen by your machine. It will see broadcast packets, and multicast packets sent to a multicast MAC address the interface is set up to receive.
You should ask the vendor of your network interface whether it supports promiscuous mode. If it does, you should ask whoever supplied the driver for the interface (the vendor, or the supplier of the OS you're running on your machine) whether it supports promiscuous mode with that network interface.
In the case of token ring interfaces, the drivers for some of them, on Windows, may require you to enable promiscuous mode in order to capture in promiscuous mode. See the Ethereal Wiki item on Token Ring capturing for details.
In the case of wireless LAN interfaces, it appears that, when those interfaces are promiscuously sniffing, they're running in a significantly different mode from the mode that they run in when they're just acting as network interfaces (to the extent that it would be a significant effor for those drivers to support for promiscuously sniffing and acting as regular network interfaces at the same time), so it may be that Windows drivers for those interfaces don't support promiscuous mode.
Q 5.2: I can't see any TCP packets other than packets to and from my machine, even though another analyzer on the network sees those packets.
A: You're probably not seeing any packets other than unicast packets to or from your machine, and broadcast and multicast packets; a switch will normally send to a port only unicast traffic sent to the MAC address for the interface on that port, and broadcast and multicast traffic - it won't send to that port unicast traffic sent to a MAC address for some other interface - and a network interface not in promiscuous mode will receive only unicast traffic sent to the MAC address for that interface, broadcast traffic, and multicast traffic sent to a multicast MAC address the interface is set up to receive.
TCP doesn't use broadcast or multicast, so you will only see your own TCP traffic, but UDP services may use broadcast or multicast so you'll see some UDP traffic - however, this is not a problem with TCP traffic, it's a problem with unicast traffic, as you also won't see all UDP traffic between other machines.
I.e., this is probably the same question as this earlier one; see the response to that question.
Q 5.3: I'm only seeing ARP packets when I try to capture traffic.
A: You're probably on a switched network, and running Ethereal on a machine that's not sending traffic to the switch and not being sent any traffic from other machines on the switch. ARP packets are often broadcast packets, which are sent to all switch ports.
I.e., this is probably the same question as this earlier one; see the response to that question.
Q 5.4: I'm running Ethereal on Windows; why does some network interface on my machine not show up in the list of interfaces in the "Interface:" field in the dialog box popped up by "Capture->Start", and/or why does Ethereal give me an error if I try to capture on that interface?
A: If you are running Ethereal on Windows NT 4.0, Windows 2000, Windows XP, or Windows Server 2003, and this is the first time you have run a WinPcap-based program (such as Ethereal, or Tethereal, or WinDump, or Analyzer, or...) since the machine was rebooted, you need to run that program from an account with administrator privileges; once you have run such a program, you will not need administrator privileges to run any such programs until you reboot.
If you are running on Windows 95/98/Me, or if you are running on Windows NT 4.0/Windows 2000/Windows XP/Windows Server 2003 and have administrator privileges or a WinPcap-based program has been run with those privileges since the machine rebooted, this problem might clear up if you completely un-install WinPcap and then re-install it.
If that doesn't work, then note that Ethereal relies on the WinPcap library, on the WinPcap device driver, and on the facilities that come with the OS on which it's running in order to do captures.
Therefore, if the OS, the WinPcap library, or the WinPcap driver don't support capturing on a particular network interface device, Ethereal won't be able to capture on that device.
Note that:
If you are having problems capturing on Token Ring interfaces, and you have WinPcap 2.02 or an earlier version of WinPcap installed, you should uninstall WinPcap, download and install the current version of WinPcap, and then install the latest version of Ethereal.
On Windows 2000, Windows XP, and Windows Server 2003, but not Windows NT 4.0 or Windows Vista Beta 1, you should be able to capture on the "GenericDialupAdapter" with WinPcap 3.1. (3.1 beta releases called it the "NdisWanAdapter"; if you're using a 3.1 beta release, you should un-install it and install the final 3.1 release.) See the Ethereal Wiki item on PPP capturing for details.
If the attempt to capture on it succeeds, the interface is somehow not being reported by the mechanism Ethereal uses to get a list of interfaces. Try listing the interfaces with WinDump; see the WinDump Web site or the local mirror of the WinDump Web site for information on using WinDump.
You would run WinDump with the -D flag; if it lists the interface, please report this to ethereal-dev@ethereal.com giving full details of the problem, including
If you are having trouble capturing on a particular network interface, first try capturing on that device with WinDump; see the WinDump Web site or the local mirror of the WinDump Web site for information on using WinDump.
If you can capture on the interface with WinDump, send mail to ethereal-users@ethereal.com giving full details of the problem, including
You may also want to ask the ethereal-users@ethereal.com and the winpcap-users@winpcap.org mailing lists to see if anybody happens to know about the problem and know a workaround or fix for the problem. (Note that you will have to subscribe to that list in order to be allowed to mail to it; see the WinPcap support page, or the local mirror of that page, for information on the mailing list.) In your mail, please give full details of the problem, as described above, and also indicate that the problem occurs with WinDump, not just with Ethereal.
Q 5.5: I'm running Ethereal on Windows; why do no network interfaces show up in the list of interfaces in the "Interface:" field in the dialog box popped up by "Capture->Start"?
A: This is really the same question as the previous one; see the response to that question.
Q 5.6: I'm running Ethereal on Windows; why doesn't my serial port/ADSL modem/ISDN modem show up in the list of interfaces in the "Interface:" field in the dialog box popped up by "Capture->Start"?
A: Internet access on those devices is often done with the Point-to-Point (PPP) protocol; WinPcap 2.3 has problems supporting PPP WAN interfaces on Windows NT 4.0, Windows 2000, Windows XP, and Windows Server 2003, and, to avoid those problems, support for PPP WAN interfaces on those versions of Windows has been disabled in WinPcap 3.0.
On Windows 2000, Windows XP, and Windows Server 2003, but not Windows NT 4.0 or Windows Vista Beta 1, you should be able to capture on the "GenericDialupAdapter" with WinPcap 3.1. (3.1 beta releases called it the "NdisWanAdapter"; if you're using a 3.1 beta release, you should un-install it and install the final 3.1 release.) See the Ethereal Wiki item on PPP capturing for details.
Q 5.7: I'm running Ethereal on a UNIX-flavored OS; why does some network interface on my machine not show up in the list of interfaces in the "Interface:" field in the dialog box popped up by "Capture->Start", and/or why does Ethereal give me an error if I try to capture on that interface?
A: You may need to run Ethereal from an account with sufficient privileges to capture packets, such as the super-user account, or may need to give your account sufficient privileges to capture packets. Only those interfaces that Ethereal can open for capturing show up in that list; if you don't have sufficient privileges to capture on any interfaces, no interfaces will show up in the list. See the Ethereal Wiki item on capture privileges for details on how to give a particular account or account group capture privileges on platforms where that can be done.
If you are running Ethereal from an account with sufficient privileges, then note that Ethereal relies on the libpcap library, and on the facilities that come with the OS on which it's running in order to do captures. On some OSes, those facilities aren't present by default; see the Ethereal Wiki item on adding capture support for details.
And, even if you're running with an account that has sufficient privileges to capture, and capture support is present in your OS, if the OS or the libpcap library don't support capturing on a particular network interface device or particular types of devices, Ethereal won't be able to capture on that device.
On Solaris, note that libpcap 0.6.2 and earlier didn't support Token Ring interfaces; the current version, 0.7.2, does support Token Ring, and the current version of Ethereal works with libcap 0.7.2 and later.
If an interface doesn't show up in the list of interfaces in the "Interface:" field, and you know the name of the interface, try entering that name in the "Interface:" field and capturing on that device.
If the attempt to capture on it succeeds, the interface is somehow not being reported by the mechanism Ethereal uses to get a list of interfaces; please report this to ethereal-dev@ethereal.com giving full details of the problem, including
If you can capture on the interface with tcpdump, send mail to ethereal-users@ethereal.com giving full details of the problem, including
You may also want to ask the ethereal-users@ethereal.com and the tcpdump-workers@tcpdump.org mailing lists to see if anybody happens to know about the problem and know a workaround or fix for the problem. In your mail, please give full details of the problem, as described above, and also indicate that the problem occurs with tcpdump not just with Ethereal.
Q 5.8: I'm running Ethereal on a UNIX-flavored OS; why do no network interfaces show up in the list of interfaces in the "Interface:" field in the dialog box popped up by "Capture->Start"?
A: This is really the same question as the previous one; see the response to that question.
Q 5.9: Can Ethereal capture on (my T1/E1 line, SS7 links, etc.)?
A: Ethereal can only capture on devices supported by libpcap/WinPcap. On most OSes, only devices that can act as network interfaces of the type that support IP are supported as capture devices for libpcap/WinPcap, although the device doesn't necessarily have to be running as an IP interface in order to support traffic capture.
On Linux and FreeBSD, libpcap 0.8 and later support the API for Endace Measurement Systems' DAG cards, so that a system with one of those cards, and its driver and libraries, installed can capture traffic with those cards with libpcap-based applications. You would either have to have a version of Ethereal built with that version of libpcap, or a dynamically-linked version of Ethereal and a shared libpcap library with DAG support, in order to do so with Ethereal. You should ask Endace whether that could be used to capture traffic on, for example, your T1/E1 link.
See the SS7 capture setup page on the Ethereal Wiki for current information on capturing SS7 traffic on TDM links.Q 5.10: How do I put an interface into promiscuous mode?
A: By not disabling promiscuous mode when running Ethereal or Tethereal.
Note, however, that:
Q 5.11: I can set a display filter just fine, but capture filters don't work.
A: Capture filters currently use a different syntax than display filters. Here's the corresponding section from the ethereal(1) man page:
"Display filters in Ethereal are very powerful; more fields are filterable in Ethereal than in other protocol analyzers, and the syntax you can use to create your filters is richer. As Ethereal progresses, expect more and more protocol fields to be allowed in display filters.
Packet capturing is performed with the pcap library. The capture filter syntax follows the rules of the pcap library. This syntax is different from the display filter syntax."
The capture filter syntax used by libpcap can be found in the tcpdump(8) man page.
Q 5.12: I'm entering valid capture filters, but I still get "parse error" errors.
A: There is a bug in some versions of libpcap/WinPcap that cause it to report parse errors even for valid expressions if a previous filter expression was invalid and got a parse error.
Try exiting and restarting Ethereal; if you are using a version of libpcap/WinPcap with this bug, this will "erase" its memory of the previous parse error. If the capture filter that got the "parse error" now works, the earlier error with that filter was probably due to this bug.
The bug was fixed in libpcap 0.6; 0.4[.x] and 0.5[.x] versions of libpcap have this bug, but 0.6[.x] and later versions don't.
Versions of WinPcap prior to 2.3 are based on pre-0.6 versions of libpcap, and have this bug; WinPcap 2.3 is based on libpcap 0.6.2, and doesn't have this bug.
If you are running Ethereal on a UNIX-flavored platform, run "ethereal -v", or select "About Ethereal..." from the "Help" menu in Ethereal, to see what version of libpcap it's using. If it's not 0.6 or later, you will need either to upgrade your OS to get a later version of libpcap, or will need to build and install a later version of libpcap from the tcpdump.org Web site and then recompile Ethereal from source with that later version of libpcap.
If you are running Ethereal on Windows with a pre-2.3 version of WinPcap, you will need to un-install WinPcap and then download and install WinPcap 2.3.
Q 5.13: I saved a filter and tried to use its name to filter the display, but I got an "Unexpected end of filter string" error.
A:
You cannot use the name of a saved display filter as a filter. To
filter the display, you can enter a display filter expression -
not the name of a saved display filter - in the
"Filter:" box at the bottom of the display, and type the
Q 5.14: Why am I seeing lots of packets with incorrect TCP checksums?
A: If the packets that have incorrect TCP checksums are all being sent by the machine on which Ethereal is running, this is probably because the network interface on which you're capturing does TCP checksum offloading. That means that the TCP checksum is added to the packet by the network interface, not by the OS's TCP/IP stack; when capturing on an interface, packets being sent by the host on which you're capturing are directly handed to the capture interface by the OS, which means that they are handed to the capture interface without a TCP checksum being added to them.
The only way to prevent this from happening would be to disable TCP checksum offloading, but
It can also be set on the Ethereal or Tethereal command line with a -o tcp.check_checksum:false command-line flag, or manually set in your preferences file by adding a tcp.check_checksum:false line.
Q 5.15: I've just installed Ethereal, and the traffic on my local LAN is boring.
A: We have a collection of strange and exotic sample capture files at http://wiki.ethereal.com/SampleCaptures
Q 5.16: When I run Ethereal on Solaris 8, it dies with a Bus Error when I start it.
A: Some versions of the GTK+ library from www.sunfreeware.org appear to be buggy, causing Ethereal to drop core with a Bus Error. Un-install those packages, and try getting the 1.2.10 version from that site, or the version from The Written Word, or the version from Sun's GNOME distribution, or the version from the supplemental software CD that comes with the Solaris media kit, or build it from source from the GTK Web site. Update the GLib library to the 1.2.10 version, from the same source, as well. (If you get the 1.2.10 versions from www.sunfreeware.org, and the problem persists, un-install them and try installing one of the other versions mentioned.)
Similar problems may exist with older versions of GTK+ for earlier versions of Solaris.
Q 5.17:
When I run Ethereal, I get an error
Gtk-CRITICAL **: file gtkwindow.c: line 3107
(gtk_window_resize): assertion `height > 0'
failed.
A: This is a bug in Ethereal 0.10.5 and 0.10.5a, which is fixed in Ethereal 0.10.6 and later releases.
Q 5.18:
When I run Tethereal with the "-x" option, it crashes with
an error
"** ERROR **: file print.c: line 691 (print_line):
should not be reached.
A: This is a bug in Ethereal 0.10.0a, which is fixed in 0.10.1 and later releases. To work around the bug, don't use "-x" unless you're also using "-V"; note that "-V" produces a full dissection of each packet, so you might not want to use it.
Q 5.19: When I run Ethereal on Windows NT, it dies with a Dr. Watson error, reporting an "Integer division by zero" exception, when I start it.
A: In at least some case, this appears to be due to using the default VGA driver; if that's not the correct driver for your video card, try running the correct driver for your video card.
Q 5.20: When I try to run Ethereal, it complains about sprint_realloc_objid being undefined.
A: Ethereal can only be linked with version 4.2.2 or later of UCD SNMP. Your version of Ethereal was dynamically linked with such a version of UCD SNMP; however, you have an older version of UCD SNMP installed, which means that when Ethereal is run, it tries to link to the older version, and fails. You will have to replace that version of UCD SNMP with version 4.2.2 or a later version.
Q 5.21: I'm running Ethereal on Linux; why do my time stamps have only 100ms resolution, rather than 1us resolution?
A: Ethereal gets time stamps from libpcap/WinPcap, and libpcap/WinPcap get them from the OS kernel, so Ethereal - and any other program using libpcap, such as tcpdump - is at the mercy of the time stamping code in the OS for time stamps.
At least on x86-based machines, Linux can get high-resolution time stamps on newer processors with the Time Stamp Counter (TSC) register; for example, Intel x86 processors, starting with the Pentium Pro, and including all x86 processors since then, have had a TSC, and other vendors probably added the TSC at some point to their families of x86 processors.
The Linux kernel must be configured with the CONFIG_X86_TSC option enabled in order to use the TSC. Make sure this option is enabled in your kernel.
In addition, some Linux distributions may have bugs in their versions of the kernel that cause packets not to be given high-resolution time stamps even if the TSC is enabled. See, for example, bug 61111 for Red Hat Linux 7.2. If your distribution has a bug such as this, you may have to run a standard kernel from kernel.org in order to get high-resolution time stamps.
Q 5.22: I'm capturing packets on {Windows 95, Windows 98, Windows Me}; why are the time stamps on packets wrong?
A: This is due to a bug in WinPcap. The bug should be fixed in WinPcap 3.0.
Q 5.23: When I try to run Ethereal on Windows, it fails to run because it can't find packet.dll.
A: In older versions of Ethereal, there were two binary distributions available for Windows, one that supported capturing packets, and one that didn't. The version that supported capturing packets required that you install the WinPcap driver; if you didn't install it, it would fail to run because it couldn't find packet.dll.
The current version of Ethereal has only one binary distribution for Windows; that version will check whether WinPcap is installed and, if it's not, will disable support for packet capture.
The WinPcap driver and libraries can be downloaded from the WinPcap Web site, the local mirror of the WinPcap Web site, or the Wiretapped.net mirror of the WinPcap site.
Q 5.24: I'm running Ethereal on Windows NT 4.0/Windows 2000/Windows XP/Windows Server 2003; my machine has a PPP (dial-up POTS, ISDN, etc.) interface, and it shows up in the "Interface" item in the "Capture Options" dialog box. Why can no packets be sent on or received from that network while I'm trying to capture traffic on that interface?
A: Some versions of WinPcap have problems with PPP WAN interfaces on Windows NT 4.0, Windows 2000, Windows XP, and Windows Server 2003; one symptom that may be seen is that attempts to capture in promiscuous mode on the interface cause the interface to be incapable of sending or receiving packets. You can disable promiscuous mode using the -p command-line flag or the item in the "Capture Preferences" dialog box, but this may mean that outgoing packets, or incoming packets, won't be seen in the capture.
On Windows 2000, Windows XP, and Windows Server 2003, but not Windows NT 4.0 or Windows Vista Beta 1, you should be able to capture on the "GenericDialupAdapter" with WinPcap 3.1. (3.1 beta releases called it the "NdisWanAdapter"; if you're using a 3.1 beta release, you should un-install it and install the final 3.1 release.) See the Ethereal Wiki item on PPP capturing for details.
Q 5.25: I'm running Ethereal on Windows 95/98/Me, on a machine with more than one network adapter of the same type; Ethereal shows all of those adapters with the same name, but I can't use any of those adapters other than the first one.
A: Unfortunately, Windows 95/98/Me gives the same name to multiple instances of the type of same network adapter. Therefore, WinPcap cannot distinguish between them, so a WinPcap-based application can capture only on the first such interface; Ethereal is a libpcap/WinPcap-based application.
Q 5.26: I'm running Ethereal on Windows, and I'm not seeing any traffic being sent by the machine running Ethereal.
A: If you are running some form of VPN client software, it might be causing this problem; people have seen this problem when they have Check Point's VPN software installed on their machine. If that's the cause of the problem, you will have to remove the VPN software in order to have Ethereal (or any other application using WinPcap) see outgoing packets; unfortunately, neither we nor the WinPcap developers know any way to make WinPcap and the VPN software work well together.
Also, some drivers for Windows (especially some wireless network interface drivers) apparently do not, when running in promiscuous mode, arrange that outgoing packets are delivered to the software that requested that the interface run promiscuously; try turning promiscuous mode off.
Q 5.27: I'm trying to capture traffic but I'm not seeing any.
A: Is the machine running Ethereal sending out any traffic on the network interface on which you're capturing, or receiving any traffic on that network, or is there any broadcast traffic on the network or multicast traffic to a multicast group to which the machine running Ethereal belongs?
If not, this may just be a problem with promiscuous sniffing, either due to running on a switched network or a dual-speed hub, or due to problems with the interface not supporting promiscuous mode; see the response to this earlier question.
Otherwise, on Windows, see the response to this question and, on a UNIX-flavored OS, see the response to this question.
Q 5.28: I have an XXX network card on my machine; if I try to capture on it, my machine crashes or resets itself.
A: This is almost certainly a problem with one or more of:
Q 5.29: My machine crashes or resets itself when I select "Start" from the "Capture" menu or select "Preferences" from the "Edit" menu.
A: Both of those operations cause Ethereal to try to build a list of the interfaces that it can open; it does so by getting a list of interfaces and trying to open them. There is probably an OS, driver, or, for Windows, WinPcap bug that causes the system to crash when this happens; see the previous question.
Q 5.30: Does Ethereal work on Windows Me?
A: Yes, but if you want to capture packets, you will need to install the latest version of WinPcap, as 2.02 and earlier versions of WinPcap didn't support Windows Me. You should also install the latest version of Ethereal as well.
Q 5.31: Does Ethereal work on Windows XP?
A: Yes, but if you want to capture packets, you will need to install the latest version of WinPcap, as 2.2 and earlier versions of WinPcap didn't support Windows XP.
Q 5.32: Why doesn't Ethereal correctly identify RTP packets? It shows them only as UDP.
A: Ethereal can identify a UDP datagram as containing a packet of a particular protocol running atop UDP only if
That leaves 3). If there's RTSP traffic that sets up an RTP session, then, at least in some cases, the RTSP dissector will set things up so that subsequent RTP traffic will be identified. Currently, that's the only place we do that; there may be other places.
However, there will always be places where Ethereal is simply incapable of deducing that a given UDP flow is RTP; a mechanism would be needed to allow the user to specify that a given conversation should be treated as RTP. As of Ethereal 0.8.16, such a mechanism exists; if you select a UDP or TCP packet, the right mouse button menu will have a "Decode As..." menu item, which will pop up a dialog box letting you specify that the source port, the destination port, or both the source and destination ports of the packet should be dissected as some particular protocol.
Q 5.33: Why doesn't Ethereal show Yahoo Messenger packets in captures that contain Yahoo Messenger traffic?
A: Ethereal only recognizes as Yahoo Messenger traffic packets to or from TCP port 3050 that begin with "YPNS", "YHOO", or "YMSG". TCP segments that start with the middle of a Yahoo Messenger packet that takes more than one TCP segment will not be recognized as Yahoo Messenger packets (even if the TCP segment also contains the beginning of another Yahoo Messenger packet).
Q 5.34:
Why do I get the error
Gdk-ERROR **: Palettized display (256-colour) mode not
supported on Windows.
when I try to run Ethereal on Windows?
aborting....
A: Ethereal is built using the GTK+ toolkit, which supports most UNIX-flavored OSes, and also supports Windows.
Windows versions of Ethereal before 0.9.14 were built with an older version of that toolkit, which didn't support 256-color mode on Windows - it required HiColor (16-bit colors) or more.
Windows versions of Ethereal 0.9.14 and later are built with a version of that toolkit that supports 256-color mode; upgrade to the current version of Ethereal if you want to run on a display in 256-color mode.
Q 5.35: When I capture on Windows in promiscuous mode, I can see packets other than those sent to or from my machine; however, those packets show up with a "Short Frame" indication, unlike packets to or from my machine. What should I do to arrange that I see those packets in their entirety?
A: In at least some cases, this appears to be the result of PGPnet running on the network interface on which you're capturing; turn it off on that interface.
Q 5.36: I'm capturing packets on a machine on a VLAN; why don't the packets I'm capturing have VLAN tags?
A: You might be capturing on what might be called a "VLAN interface" - the way a particular OS makes VLANs plug into the networking stack might, for example, be to have a network device object for the physical interface, which takes VLAN packets, strips off the VLAN header and constructs an Ethernet header, and passes that packet to an internal network device object for the VLAN, which then passes the packets onto various higher-level protocol implementations.
In order to see the raw Ethernet packets, rather than "de-VLANized" packets, you would have to capture not on the virtual interface for the VLAN, but on the interface corresponding to the physical network device, if possible. See the Ethereal Wiki item on VLAN capturing for details.
Q 5.37: How can I capture raw 802.11 frames, including non-data (management, beacon) frames?
A: That depends on the operating system on which you're running, and on the 802.11 interface on which you're capturing.
This would probably require that you capture in promiscuous mode or in the mode called "monitor mode" or "RFMON mode". On some platforms, or with some cards, this might require that you capture in monitor mode - promiscuous mode might not be sufficient. If you want to capture traffic on networks other than the one with which you're associated, you will have to capture in monitor mode.
Not all operating systems support capturing non-data packets and, even on operating systems that do support it, not all drivers, and thus not all interfaces, support it. Even on those that do, monitor mode might not be supported by the operating system or by the drivers for all interfaces.
NOTE: an interface running in monitor mode will, on most if not all platforms, not be able to act as a regular network interface; putting it into monitor mode will, in effect, take your machine off of whatever network it's on as long as the interface is in monitor mode, allowing it only to passively capture packets.
This means that you should disable name resolution when capturing in monitor mode; otherwise, when Ethereal (or Tethereal, or tcpdump) tries to display IP addresses as host names, it will probably block for a long time trying to resolve the name because it will not be able to communicate with any DNS or NIS servers.
See the Ethereal Wiki item on 802.11 capturing for details.
Q 5.38: How do I capture on an 802.11 device in monitor mode?
A: Whether you will be able to capture in monitor mode depends on the operating system, adapter, and driver you're using. See the previous question for information on monitor mode, including a link to the Ethereal Wiki page that gives details on 802.11 capturing.
Q 5.39: I'm trying to capture 802.11 traffic on Windows; why am I not seeing any packets?
A: At least some 802.11 card drivers on Windows appear not to see any packets if they're running in promiscuous mode. Try turning promiscuous mode off; you'll only be able to see packets sent by and received by your machine, not third-party traffic, and it'll look like Ethernet traffic and won't include any management or control frames, but that's a limitation of the card drivers.
See MicroLogix's list of cards supported with WinPcap for information on support of various adapters and drivers with WinPcap.
Q 5.40: I'm trying to capture 802.11 traffic on Windows; why am I seeing packets received by the machine on which I'm capturing traffic, but not packets sent by that machine?
A: This appears to be another problem with promiscuous mode; try turning it off.
Q 5.41: How can I capture packets with CRC errors?
A: Ethereal can capture only the packets that the packet capture library - libpcap on UNIX-flavored OSes, and the WinPcap port to Windows of libpcap on Windows - can capture, and libpcap/WinPcap can capture only the packets that the OS's raw packet capture mechanism (or the WinPcap driver, and the underlying OS networking code and network interface drivers, on Windows) will allow it to capture.
Unless the OS always supplies packets with errors such as invalid CRCs to the raw packet capture mechanism, or can be configured to do so, invalid CRCs to the raw packet capture mechanism, Ethereal - and other programs that capture raw packets, such as tcpdump - cannot capture those packets. You will have to determine whether your OS needs to be so configured and, if so, can be so configured, configure it if necessary and possible, and make whatever changes to libpcap and the packet capture program you're using are necessary, if any, to support capturing those packets.
Most OSes probably do not support capturing packets with invalid CRCs on Ethernet, and probably do not support it on most other link-layer types. Some drivers on some OSes do support it, such as some Ethernet drivers on FreeBSD; in those OSes, you might always get those packets, or you might only get them if you capture in promiscuous mode (you'd have to determine which is the case).
Note that libpcap does not currently supply to programs that use it an indication of whether the packet's CRC was invalid (because the drivers themselves do not supply that information to the raw packet capture mechanism); therefore, Ethereal will not indicate which packets had CRC errors unless the FCS was captured (see the next question) and you're using Ethereal 0.9.15 and later, in which case Ethereal will check the CRC and indicate whether it's correct or not.
Q 5.42: How can I capture entire frames, including the FCS?
A: Ethereal can only capture data that the packet capture library - libpcap on UNIX-flavored OSes, and the WinPcap port to Windows of libpcap on Windows - can capture, and libpcap/WinPcap can capture only the data that the OS's raw packet capture mechanism (or the WinPcap driver, and the underlying OS networking code and network interface drivers, on Windows) will allow it to capture.
For any particular link-layer network type, unless the OS supplies the FCS of a frame as part of the frame, or can be configured to do so, Ethereal - and other programs that capture raw packets, such as tcpdump - cannot capture the FCS of a frame. You will have to determine whether your OS needs to be so configured and, if so, can be so configured, configure it if necessary and possible, and make whatever changes to libpcap and the packet capture program you're using are necessary, if any, to support capturing the FCS of a frame.
Most OSes do not support capturing the FCS of a frame on Ethernet, and probably do not support it on most other link-layer types. Some drivres on some OSes do support it, such as some (all?) Ethernet drivers on NetBSD and possibly the driver for Apple's gigabit Ethernet interface in Mac OS X; in those OSes, you might always get the FCS, or you might only get the FCS if you capture in promiscuous mode (you'd have to determine which is the case).
Versions of Ethereal prior to 0.9.15 will not treat an Ethernet FCS in a captured packet as an FCS. 0.9.15 and later will attempt to determine whether there's an FCS at the end of the frame and, if it thinks there is, will display it as such, and will check whether it's the correct CRC-32 value or not.
Q 5.43: Why does Ethereal hang after I stop a capture?
A: The most likely reason for this is that Ethereal is trying to look up an IP address in the capture to convert it to a name (so that, for example, it can display the name in the source address or destination address columns), and that lookup process is taking a very long time.
Ethereal calls a routine in the OS of the machine on which it's running to convert of IP addresses to the corresponding names. That routine probably does one or more of:
If a DNS server that's used in an address lookup is not responding, the lookup will fail, but will only fail after a timeout while the system routine waits for a reply.
In addition, on Windows systems, if the DNS lookup of the address fails, either because the server isn't responding or because there are no records in the DNS that could be used to map the address to a name, a NetBIOS-over-TCP query will be made. That query involves sending a message to the NetBIOS-over-TCP name service on that machine, asking for the name and other information about the machine. If the machine isn't running software that responds to those queries - for example, many non-Windows machines wouldn't be running that software - the lookup will only fail after a timeout. Those timeouts can cause the lookup to take a long time.
If you disable network address-to-name translation - for example, by turning off the "Enable network name resolution" option in the "Capture Options" dialog box for starting a network capture - the lookups of the address won't be done, which may speed up the process of reading the capture file after the capture is stopped. You can make that setting the default by selecting "Preferences" from the "Edit" menu, turning off the "Enable network name resolution" option in the "Name resolution" options in the preferences disalog box, and using the "Save" button in that dialog box; note that this will save all your current preference settings.
If Ethereal hangs when reading a capture even with network name resolution turned off, there might, for example, be a bug in one of Ethereal's dissectors for a protocol causing it to loop infinitely. If you're not running the most recent release of Ethereal, you should first upgrade to that release, as, if there's a bug of that sort, it might've been fixed in a release after the one you're running. If the hang occurs in the most recent release of Ethereal, the bug should be reported to the Ethereal developers' mailing list at ethereal-dev@ethereal.com.
On UNIX-flavored OSes, please try to force Ethereal to dump core, by sending it a SIGABRT signal (usually signal 6) with the kill command, and then get a stack trace if you have a debugger installed. A stack trace can be obtained by using your debugger (gdb in this example), the Ethereal binary, and the resulting core file. Here's an example of how to use the gdb command backtrace to do so.
$ gdb ethereal core
(gdb) backtrace
..... prints the stack trace
(gdb) quit
$
The core dump file may be named "ethereal.core" rather than "core" on
some platforms (e.g., BSD systems).Also, if at all possible, please send a copy of the capture file that caused the problem; when capturing packets, Ethereal normally writes captured packets to a temporary file, which will probably be in /tmp or /var/tmp on UNIX-flavored OSes, \TEMP on the main system disk (normally C:) on Windows 9x/Me/NT 4.0, and \Documents and Settings\your login name\Local Settings\Temp on the main system disk on Windows 2000/Windows XP/Windows Server 2003, so the capture file will probably be there. It will have a name beginning with ether, with some mixture of letters and numbers after that. Please don't send a trace file greater than 1 MB when compressed; instead, make it available via FTP or HTTP, or say it's available but leave it up to a developer to ask for it. If the trace file contains sensitive information (e.g., passwords), then please do not send it.
Q 5.44: How can I search for, or filter, packets that have a particular string anywhere in them?
A: If you want to do this when capturing, you can't. That's a feature that would be hard to implement in capture filters without changes to the capture filter code, which, on many platforms, is in the OS kernel and, on other platforms, is in the libpcap library.
In releases prior to 0.9.14, you also can't search for, or filter, packets containing a particular string even after you've captured them.
In 0.9.14, you can search for, but not filter, packets that have a particular string; this has been added to the "Find Frame" dialog ("Find Frame" under the "Edit" menu, or control-F).
In 0.9.15 and later, you can search for those packets using either the mechanism introduced in 0.9.14 or using the new "contains" operator in filter expressions, which lets you search the entire packet or text string or byte string fields in the packet; the "contains" operator can also be used in expressions used to filter the display.
Q 5.45: How do I filter a capture to see traffic for virus XXX?
A: For some viruses/worms there might be a capture filter to recognize the virus traffic. Check the CaptureFilters page on the Ethereal Wiki to see if anybody's added such a filter.
Note that Ethereal was not designed to be an intrusion detection system; you might be able to use it as an IDS, but in most cases software designed to be an IDS, such as Snort or Prelude, will probably work better.
The Bleeding Edge of Snort has a collection of signatures for Snort to detect various viruses, worms, and the like.