tethereal - Dump and analyze network traffic

tethereal [ -a <capture autostop condition> ] ... [ -b <capture ring buffer option>] ... [ -B <capture buffer size (Win32 only)> ] [ -c <capture packet count> ] [ -d <layer type>==<selector>,<decode-as protocol> ] [ -D ] [ -f <capture filter> ] [ -F <file format> ] [ -h ] [ -i <capture interface>|- ] [ -l ] [ -L ] [ -n ] [ -N <name resolving flags> ] [ -o <preference setting> ] ... [ -p ] [ -q ] [ -r <infile> ] [ -R <read (display) filter> ] [ -s <capture snaplen> ] [ -S ] [ -t ad|a|r|d ] [ -T pdml|psml|ps|text ] [ -v ] [ -V ] [ -w <outfile>|- ] [ -x ] [ -X <eXtension option>] [ -y <capture link type> ] [ -z <statistics> ]

Tethereal is a network protocol analyzer. It lets you capture packet data from a live network, or read packets from a previously saved capture file, either printing a decoded form of those packets to the standard output or writing the packets to a file. Tethereal's native capture file format is libpcap format, which is also the format used by tcpdump and various other tools.

Without any options set, Tethereal will work much like tcpdump. It will use the pcap library to capture traffic from the first available network interface and displays a summary line on stdout for each received packet.

Tethereal is able to detect, read and write the same capture files that are supported by Ethereal. The input file doesn't need a specific filename extension, the file format and an optional gzip compression will be automatically detected. The capture file format section of ethereal(1) or http://www.ethereal.com/docs/man-pages/ethereal.1.html provides a detailed description.

Compressed file support uses (and therefore requires) the zlib library. If the zlib library is not present, Tethereal will compile, but will be unable to read compressed files.

If the -w option is not specified, Tethereal writes to the standard output the text of a decoded form of the packets it captures or reads. If the -w option is specified, Tethereal writes to the file specified by that option the raw data of the packets, along with the packets' time stamps.

When writing a decoded form of packets, Tethereal writes, by default, a summary line containing the fields specified by the preferences file (which are also the fields displayed in the packet list pane in Ethereal), although if it's writing packets as it captures them, rather than writting packets from a saved capture file, it won't show the frame number field. If the -V option is specified, it writes instead a view of the details of the packet, showing all the fields of all protocols in the packet.

If you want to write the decoded form of packets to a file, run Tethereal without the -w option, and redirect its standard output to the file (do not use the -w option).

When writing packets to a file, Tethereal, by default, writes the file in libpcap format, and writes all of the packets it sees to the output file. The -F option can be used to specify the format in which to write the file. This list of available file formats is displayed by the -h flag.

Read filters in Tethereal, which allow you to select which packets are to be decoded or written to a file, are very powerful; more fields are filterable in Tethereal than in other protocol analyzers, and the syntax you can use to create your filters is richer. As Tethereal progresses, expect more and more protocol fields to be allowed in read 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 read filter syntax. A read filter can also be specified when capturing, and only packets that pass the read filter will be displayed or saved to the output file; note, however, that capture filters are much more efficient than read filters, and it may be more difficult for Tethereal to keep up with a busy network if a read filter is specified for a live capture.

A capture or read filter can either be specified with the -f or -R option, respectively, in which case the entire filter expression must be specified as a single argument (which means that if it contains spaces, it must be quoted), or can be specified with command-line arguments after the option arguments, in which case all the arguments after the filter arguments are treated as a filter expression. Capture filters are supported only when doing a live capture; read filters are supported when doing a live capture and when reading a capture file, but require Tethereal to do more work when filtering, so you might be more likely to lose packets under heavy load if you're using a read filter. If the filter is specified with command-line arguments after the option arguments, it's a capture filter if a capture is being done (i.e., if no -r option was specified) and a read filter if a capture file is being read (i.e., if a -r option was specified).

-a <capture autostop condition>

Specify a criterion that specifies when Tethereal is to stop writing to a capture file. The criterion is of the form test:value, where test is one of: duration:value Stop writing to a capture file after value seconds have elapsed. filesize:value Stop writing to a capture file after it reaches a size of value kilobytes (where a kilobyte is 1024 bytes). If this option is used together with the -b option, Ethereal will stop writing to the current capture file and switch to the next one if filesize is reached. files:value Stop writing to capture files after value number of files were written.

-b <capture ring buffer option>

Cause Tethereal to run in multiple files mode. In multiple files mode, Tethereal will write to several capture files. When the first capture file fills up, Tethereal will switch writing to the next file and so on. The created filenames are based on the filename given with the -w option, the number of the file and on the creation date and time, e.g. outfile_00001_20050604120117.pcap, outfile_00001_20050604120523.pcap, ... With the files option it's also possible to form a ring buffer. This will fill up new files until the number of files specified, at which point Tethereal will discard the data in the first file and start writing to that file and so on. If the files option is not set, new files filled up until one of the capture stop conditions match (or until the disk if full). The criterion is of the form key:value, where key is one of: duration:value switch to the next file after value seconds have elapsed, even if the current file is not completely filled up. filesize:value switch to the next file after it reaches a size of value kilobytes (where a kilobyte is 1024 bytes). files:value begin again with the first file after value number of files were written (form a ring buffer).

-B <capture buffer size (Win32 only)>

Win32 only: set capture buffer size (in MB, default is 1MB). This is used by the the capture driver to buffer packet data until that data can be written to disk. If you encounter packet drops while capturing, try to increase this size.

-c <capture packet count>

Set the maximum number of packets to read when capturing live data.

-d <layer type>==<selector>,<decode-as protocol>

Specify that if the layer type in question (for example, tcp.port or udp.port for a TCP or UDP port number) has the specified selector value, packets should be dissected as the specified protocol. Example: -d tcp.port==8888,http will decode any traffic running over TCP port 8888 as HTTP.

-D

Print a list of the interfaces on which Tethereal can capture, and exit. For each network interface, a number and an interface name, possibly followed by a text description of the interface, is printed. The interface name or the number can be supplied to the -i option to specify an interface on which to capture. This can be useful on systems that don't have a command to list them (e.g., Windows systems, or UNIX systems lacking ifconfig -a); the number can be useful on Windows 2000 and later systems, where the interface name is a somewhat complex string. Note that can capture means that Tethereal was able to open that device to do a live capture. Depending on your system you may need to run tethereal from an account with special privileges (for example, as root) to be able to capture network traffic. If Tethereal -D is not run from such an account, it will not list any interfaces.

-f <capture filter>

Set the capture filter expression.

-F <file format>

Set the file format of the output capture file written using the -w option. The output written with the -w option is raw packet data, not text, so there is no -F option to request text output.

-h

Print the version and options and exits.

-i <capture interface>|-

Set the name of the network interface or pipe to use for live packet capture. Network interface names should match one of the names listed in "tethereal -D (described above); a number, as reported by tethereal -D, can also be used. If you're using UNIX, netstat -i or ifconfig -a" might also work to list interface names, although not all versions of UNIX support the -a option to ifconfig. If no interface is specified, Tethereal searches the list of interfaces, choosing the first non-loopback interface if there are any non-loopback interfaces, and choosing the first loopback interface if there are no non-loopback interfaces. If there are no interfaces at all, Tethereal reports an error and doesn't start the capture. Pipe names should be either the name of a FIFO (named pipe) or ``-'' to read data from the standard input. Data read from pipes must be in standard libpcap format. Note: the Win32 version of Tethereal doesn't support capturing from pipes or stdin!

-l

Flush the standard output after the information for each packet is printed. (This is not, strictly speaking, line-buffered if -V was specified; however, it is the same as line-buffered if -V wasn't specified, as only one line is printed for each packet, and, as -l is normally used when piping a live capture to a program or script, so that output for a packet shows up as soon as the packet is seen and dissected, it should work just as well as true line-buffering. We do this as a workaround for a deficiency in the Microsoft Visual C library.) This may be useful when piping the output of Tethereal to another program, as it means that the program to which the output is piped will see the dissected data for a packet as soon as Tethereal sees the packet and generates that output, rather than seeing it only when the standard output buffer containing that data fills up.

-L

List the data link types supported by the interface and exit. The reported link types can be used for the -y option.

-n

Disable network object name resolution (such as hostname, TCP and UDP port names), the -N flag might override this one.

-N <name resolving flags>

Turn on name resolving only for particular types of addresses and port numbers, with name resolving for other types of addresses and port numbers turned off. This flag overrides -n if both -N and -n are present. If both -N and -n flags are not present, all name resolutions are turned on. The argument is a string that may contain the letters: m to enable MAC address resolution n to enable network address resolution t to enable transport-layer port number resolution C to enable concurrent (asynchronous) DNS lookups

-o <preference>:<value>

Set a preference value, overriding the default value and any value read from a preference file. The argument to the option is a string of the form prefname:value, where prefname is the name of the preference (which is the same name that would appear in the preference file), and value is the value to which it should be set.

-p

Don't put the interface into promiscuous mode. Note that the interface might be in promiscuous mode for some other reason; hence, -p cannot be used to ensure that the only traffic that is captured is traffic sent to or from the machine on which Tethereal is running, broadcast traffic, and multicast traffic to addresses received by that machine.

-q

When capturing packets, don't display the continuous count of packets captured that is normally shown when saving a capture to a file; instead, just display, at the end of the capture, a count of packets captured. On systems that support the SIGINFO signal, such as various BSDs, you can cause the current count to be displayed by typing your status character (typically control-T, although it might be set to disabled by default on at least some BSDs, so you'd have to explicitly set it to use it). When reading a capture file, or when capturing and not saving to a file, don't print packet information; this is useful if you're using a -z option to calculate statistics and don't want the packet information printed, just the statistics.

-r <infile>

Read packet data from infile, can be any supported capture file format (including gzipped files). It's not possible to use named pipes or stdin here!

-R <read (display) filter>

Cause the specified filter (which uses the syntax of read/display filters, rather than that of capture filters) to be applied before printing a decoded form of packets or writing packets to a file; packets not matching the filter are discarded rather than being printed or written.

-s <capture snaplen>

Set the default snapshot length to use when capturing live data. No more than snaplen bytes of each network packet will be read into memory, or saved to disk.

-S

Decode and display packets even while writing raw packet data using the -w option.

-t ad|a|r|d

Set the format of the packet timestamp printed in summary lines, the default is relative. The format can be one of: ad absolute with date: The absolute date and time is the actual time and date the packet was captured a absolute: The absolute time is the actual time the packet was captured, with no date displayed r relative: The relative time is the time elapsed between the first packet and the current packet d delta: The delta time is the time since the previous packet was captured

-T pdml|psml|ps|text

Set the format of the output when viewing decoded packet data. The options are one of: pdml Packet Details Markup Language, an XML-based format for the details of a decoded packet. This information is equivalent to the packet details printed with the -V flag. psml Packet Summary Markup Language, an XML-based format for the summary information of a decoded packet. This information is equivalent to the information shown in the one-line summary printed by default. ps PostScript for a human-readable one-line summary of each of the packets, or a multi-line view of the details of each of the packets, depending on whether the -V flag was specified. text Text of a human-readable one-line summary of each of the packets, or a multi-line view of the details of each of the packets, depending on whether the -V flag was specified. This is the default.

-v

Print the version and exit.

-V

Cause Tethereal to print a view of the packet details rather than a one-line summary of the packet.

-w <outfile>|-

Write raw packet data to outfile or to the standard output if outfile is '-'. NOTE: -w provides raw packet data, not text. If you want text output you need to redirect stdout (e.g. using '>'), don't use the -w option for this.

-x

Cause Tethereal to print a hex and ASCII dump of the packet data after printing the summary or details.

-X <eXtension options>

Specify an option to be passed to a Tethereal module. The eXtension option is in the form extension_key:value, where extension_key can be: lua_script:lua_script_filename tells Ethereal to load the given script in addition to the default Lua scripts.

-y <capture link type>

Set the data link type to use while capturing packets. The values reported by -L are the values that can be used.

-z <statistics>

Get Tethereal to collect various types of statistics and display the result after finishing reading the capture file. Use the -q flag if you're reading a capture file and only want the statistics printed, not any per-packet information. Note that the -z proto option is different - it doesn't cause statistics to be gathered and printed when the capture is complete, it modifies the regular packet summary output to include the values of fields specified with the option. Therefore you must not use the -q option, as that option would suppress the printing of the regular packet summary output, and must also not use the -V option, as that would cause packet detail information rather than packet summary information to be printed. Currently implemented statistics are: -z dcerpc,rtt,uuid,major.minor[,filter] Collect call/reply RTT data for DCERPC interface uuid, version major.minor. Data collected is number of calls for each procedure, MinRTT, MaxRTT and AvgRTT. Example: use -z dcerpc,rtt,12345778-1234-abcd-ef00-0123456789ac,1.0 to collect data for CIFS SAMR Interface. This option can be used multiple times on the command line. If the optional filterstring is provided, the stats will only be calculated on those calls that match that filter. Example: use -z dcerpc,rtt,12345778-1234-abcd-ef00-0123456789ac,1.0,ip.addr==1.2.3.4 to collect SAMR RTT statistics for a specific host. -z io,phs[,filter] Create Protocol Hierarchy Statistics listing both number of packets and bytes. If no filter is specified the statistics will be calculated for all packets. If a filters is specified statistics will be only calculated for those packets that match the filter. This option can be used multiple times on the command line. -z io,stat,interval[,filter][,filter][,filter]... Collect packet/bytes statistics for the capture in intervals of interval seconds. Intervals can be specified either as whole or fractional seconds. Interval can be specified in ms resolution. If no filter is specified the statistics will be calculated for all packets. If one or more filters are specified statistics will be calculated for all filters and presented with one column of statistics for each filter. This option can be used multiple times on the command line. Example: -z io,stat,1,ip.addr==1.2.3.4 to generate 1 second statistics for all traffic to/from host 1.2.3.4. Example: -z io,stat,0.001,smb&&ip.addr==1.2.3.4 to generate 1ms statistics for all SMB packets to/from host 1.2.3.4. The examples above all use the standard syntax for generating statistics which only calculates the number of packets and bytes in each interval. io,stat can also do much more statistics and calculate COUNT(), SUM(), MIN(), MAX(), and AVG() using a slightly different filter syntax:

  [COUNT|SUM|MIN|MAX|AVG](<field>)<filter>

One important thing to note here is that the field that the calculation is based on MUST also be part of the filter string or else the calculation will fail. So: -z io,stat,0.010,AVG(smb.time) does not work. Use -z io,stat,0.010,AVG(smb.time)smb.time instead. Also be aware that a field can exist multiple times inside the same packet and will then be counted multiple times in those packets. COUNT(<field>) can be used on any type which has a display filter name. It will count how many times this particular field is encountered in the filtered packet list. Example: -z io,stat,0.010,COUNT(smb.sid)smb.sid This will count the total number of SIDs seen in each 10ms interval. SUM(<field>) can only be used on named fields of integer type. This will sum together every occurence of this fields value for each interval. Example: -z io,stat,0.010,SUM(frame.pkt_len)frame.pkt_len This will report the total number of bytes seen in all the packets within an interval. MIN/MAX/AVG(<field>) can only be used on named fields that are either integers or relative time fields. This will calculate maximum/minimum or average seen in each interval. If the field is a relative time field the output will be presented in seconds and three digits after the decimal point. The resolution for time calculations is 1ms and anything smaller will be truncated. Example: -z io,stat,0.010,smb.time&&ip.addr==1.1.1.1,MIN(smb.time)smb.time&&ip.addr==1.1.1.1,MAX(smb.time)smb.time&&ip.addr==1.1.1.1,MAX(smb.time)smb.time&&ip.addr==1.1.1.1 This will calculate statistics for all smb response times we see to/from host 1.1.1.1 in 10ms intervals. The output will be displayed in 4 columns; number of packets/bytes, minimum response time, maximum response time and average response time. -z conv,type[,filter] Create a table that lists all conversations that could be seen in the capture. type specifies which type of conversation we want to generate the statistics for; currently the supported ones are

  "eth"   Ethernet
  "fc"    Fibre Channel
  "fddi"  FDDI
  "ip"    IP addresses
  "ipx"   IPX addresses
  "tcp"   TCP/IP socket pairs  Both IPv4 and IPv6 are supported
  "tr"    Token Ring
  "udp"   UDP/IP socket pairs  Both IPv4 and IPv6 are supported

If the optional filter string is specified, only those packets that match the filter will be used in the calculations. The table is presented with one line for each conversation and displays number of packets/bytes in each direction as well as total number of packets/bytes. The table is sorted according to total number of bytes. -z proto,colinfo,filter,field Append all field values for the packet to the Info column of the one-line summary output. This feature can be used to append arbitrary fields to the Info column in addition to the normal content of that column. field is the display-filter name of a field which value should be placed in the Info column. filter is a filter string that controls for which packets the field value will be presented in the info column. field will only be presented in the Info column for the packets which match filter. NOTE: In order for Tethereal to be able to extract the field value from the packet, field MUST be part of the filter string. If not, Tethereal will not be able to extract its value. For a simple example to add the nfs.fh.hash field to the Info column for all packets containing the nfs.fh.hash field, use -z proto,colinfo,nfs.fh.hash,nfs.fh.hash To put nfs.fh.hash in the Info column but only for packets coming from host 1.2.3.4 use: -z proto,colinfo,nfs.fh.hash && ip.src==1.2.3.4,nfs.fh.hash This option can be used multiple times on the command line. -z rpc,rtt,program,version[,filter] Collect call/reply RTT data for program/version. Data collected is number of calls for each procedure, MinRTT, MaxRTT and AvgRTT. Example: use -z rpc,rtt,100003,3 to collect data for NFS v3. This option can be used multiple times on the command line. If the optional filterstring is provided, the stats will only be calculated on those calls that match that filter. Example: use -z rpc,rtt,100003,3,nfs.fh.hash==0x12345678 to collect NFS v3 RTT statistics for a specific file. -z rpc,programs Collect call/reply RTT data for all known ONC-RPC programs/versions. Data collected is number of calls for each protocol/version, MinRTT, MaxRTT and AvgRTT. This option can only be used once on the command line. -z smb,rtt[,filter] Collect call/reply RTT data for SMB. Data collected is number of calls for each SMB command, MinRTT, MaxRTT and AvgRTT. Example: use -z smb,rtt. The data will be presented as separate tables for all normal SMB commands, all Transaction2 commands and all NT Transaction commands. Only those commands that are seen in the capture will have its stats displayed. Only the first command in a xAndX command chain will be used in the calculation. So for common SessionSetupAndX + TreeConnectAndX chains, only the SessionSetupAndX call will be used in the statistics. This is a flaw that might be fixed in the future. This option can be used multiple times on the command line. If the optional filterstring is provided, the stats will only be calculated on those calls that match that filter. Example: use -z smb,rtt,ip.addr==1.2.3.4 to only collect stats for SMB packets echanged by the host at IP address 1.2.3.4 . -z smb,sids When this feature is used Tethereal will print a report with all the discovered SID and account name mappings. Only those SIDs where the account name is known will be presented in the table. For this feature to work you will need to either to enable Edit/Preferences/Protocols/SMB/Snoop SID to name mappings in the preferences or you can override the preferences by specifying -o smb.sid_name_snooping:TRUE on the Tethereal command line. The current methods used by Tethereal to find the SID->name mapping is relatively restricted but is hoped to be expanded in the future. -z mgcp,rtd[,filter] Collect requests/response RTD (Response Time Delay) data for MGCP. This is similar to -z smb,rtt). Data collected is number of calls for each known MGCP Type, MinRTD, MaxRTD and AvgRTD. Additionally you get the number of duplicate requests/responses, unresponded requests, responses ,which don't match with any request. Example: use -z mgcp,rtd. This option can be used multiple times on the command line. If the optional filterstring is provided, the stats will only be calculated on those calls that match that filter. Example: use -z mgcp,rtd,ip.addr==1.2.3.4 to only collect stats for MGCP packets exchanged by the host at IP address 1.2.3.4 . -z h225,counter[,filter] Count ITU-T H.225 messages and their reasons. In the first column you get a list of H.225 messages and H.225 message reasons, which occur in the current capture file. The number of occurences of each message or reason is displayed in the second column. Example: use -z h225,counter. This option can be used multiple times on the command line. If the optional filterstring is provided, the stats will only be calculated on those calls that match that filter. Example: use -z h225,counter,ip.addr==1.2.3.4 to only collect stats for H.225 packets exchanged by the host at IP address 1.2.3.4 . -z h225,srt[,filter] Collect requests/response SRT (Service Response Time) data for ITU-T H.225 RAS. Data collected is number of calls of each ITU-T H.225 RAS Message Type, Minimum SRT, Maximum SRT, Average SRT, Minimum in Frame, and Maximum in Frame. You will also get the number of Open Requests (Unresponded Requests), Discarded Responses (Responses without matching request) and Duplicate Messages. Example: use -z h225,srt. This option can be used multiple times on the command line. If the optional filterstring is provided, the stats will only be calculated on those calls that match that filter. Example: use -z h225,srt,ip.addr==1.2.3.4 to only collect stats for ITU-T H.225 RAS packets exchanged by the host at IP address 1.2.3.4 . -z sip,stat[,filter] This option will activate a counter for SIP messages. You will get the number of occurences of each SIP Method and of each SIP Status-Code. Additionally you also get the number of resent SIP Messages (only for SIP over UDP). Example: use -z sip,stat. This option can be used multiple times on the command line. If the optional filter string is provided, the stats will only be calculated on those calls that match that filter. Example: use -z sip,stat,ip.addr==1.2.3.4 to only collect stats for SIP packets exchanged by the host at IP address 1.2.3.4 .

See the manual page of tcpdump(8).

For a complete table of protocol and protocol fields that are filterable in Tethereal see the ethereal-filter(4) manual page.

These files contains various Ethereal configuration values.

Preferences

The preferences files contain global (system-wide) and personal preference settings. If the system-wide preference file exists, it is read first, overriding the default settings. If the personal preferences file exists, it is read next, overriding any previous values. Note: If the command line option -o is used (possibly more than once), it will in turn override values from the preferences files. The preferences settings are in the form prefname:value, one per line, where prefname is the name of the preference and value is the value to which it should be set; white space is allowed between : and value. A preference setting can be continued on subsequent lines by indenting the continuation lines with white space. A # character starts a comment that runs to the end of the line:

  # Capture in promiscuous mode?
  # TRUE or FALSE (case-insensitive).
  capture.prom_mode: TRUE

The global preferences file is looked for in the ethereal directory under the share subdirectory of the main installation directory (for example, /usr/local/share/ethereal/preferences) on UNIX-compatible systems, and in the main installation directory (for example, C:\Program Files\Ethereal\preferences) on Windows systems. The personal preferences file is looked for in $HOME/.ethereal/preferences on UNIX-compatible systems and %APPDATA%\Ethereal\preferences (or, if CW%APPDATA% isn't defined, %USERPROFILE%\Application Data\Ethereal\preferences) on Windows systems.

Disabled (Enabled) Protocols

The disabled_protos files contain system-wide and personal lists of protocols that have been disabled, so that their dissectors are never called. The files contain protocol names, one per line, where the protocol name is the same name that would be used in a display filter for the protocol:

  http
  tcp     # a comment

The global disabled_protos file uses the same directory as the global preferences file. The personal disabled_protos file uses the same directory as the personal preferences file.

Name Resolution (hosts)

If the personal hosts file exists, it is used to resolve IPv4 and IPv6 addresses before any other attempts are made to resolve them. The file has the standard hosts file syntax; each line contains one IP address and name, separated by whitespace. The same directory as for the personal preferences file is used.

Name Resolution (ethers)

The ethers files are consulted to correlate 6-byte hardware addresses to names. First the personal ethers file is tried and if an address is not found there the global ethers file is tried next. Each line contains one hardware address and name, separated by whitespace. The digits of the hardware address are separated by colons (:), dashes (-) or periods (.). The same separator character must be used consistently in an address. The following three lines are valid lines of an ethers file:

  ff:ff:ff:ff:ff:ff          Broadcast
  c0-00-ff-ff-ff-ff          TR_broadcast
  00.00.00.00.00.00          Zero_broadcast

The global ethers file is looked for in the /etc directory on UNIX-compatible systems, and in the main installation directory (for example, C:\Program Files\Ethereal) on Windows systems. The personal ethers file is looked for in the same directory as the personal preferences file.

Name Resolution (manuf)

The manuf file is used to match the 3-byte vendor portion of a 6-byte hardware address with the manufacturer's name; it can also contain well-known MAC addresses and address ranges specified with a netmask. The format of the file is the same as the ethers files, except that entries of the form:

  00:00:0C      Cisco

can be provided, with the 3-byte OUI and the name for a vendor, and entries such as:

  00-00-0C-07-AC/40     All-HSRP-routers

can be specified, with a MAC address and a mask indicating how many bits of the address must match. The above entry, for example, has 40 significant bits, or 5 bytes, and would match addresses from 00-00-0C-07-AC-00 through 00-00-0C-07-AC-FF. The mask need not be a multiple of 8. The manuf file is looked for in the same directory as the global preferences file.

Name Resolution (ipxnets)

The ipxnets files are used to correlate 4-byte IPX network numbers to names. First the global ipxnets file is tried and if that address is not found there the personal one is tried next. The format is the same as the ethers file, except that each address is four bytes instead of six. Additionally, the address can be represented as a single hexadecimal number, as is more common in the IPX world, rather than four hex octets. For example, these four lines are valid lines of an ipxnets file:

  C0.A8.2C.00              HR
  c0-a8-1c-00              CEO
  00:00:BE:EF              IT_Server1
  110f                     FileServer3

The global ipxnets file is looked for in the /etc directory on UNIX-compatible systems, and in the main installation directory (for example, C:\Program Files\Ethereal) on Windows systems. The personal ipxnets file is looked for in the same directory as the personal preferences file.

ethereal-filter(4) ethereal(1), editcap(1), tcpdump(8), pcap(3)

Tethereal is part of the Ethereal distribution. The latest version of Ethereal can be found at http://www.ethereal.com.

HTML versions of the Ethereal project man pages are available at: http://www.ethereal.com/docs/man-pages

Tethereal uses the same packet dissection code that Ethereal does, as well as using many other modules from Ethereal; see the list of authors in the Ethereal man page for a list of authors of that code.