Besides the Wireshark GUI application, there are some command line tools which can be helpful for doing some more specialized things. These tools will be described in this chapter.

TShark is a terminal oriented version of Wireshark designed for capturing and displaying packets when an interactive user interface isn't necessary or available. It supports the same options as wireshark. For more information on tshark, see the manual pages (man tshark).

There are occasions when you want to capture packets using tcpdump rather than wireshark, especially when you want to do a remote capture and do not want the network load associated with running Wireshark remotely (not to mention all the X traffic polluting your capture). However, the default tcpdump parameters result in a capture file where each packet is truncated, because most versions of tcpdump, will, by default, only capture the first 68 or 96 bytes of each packet. To ensure that you capture complete packets, use the following command: tcpdump -i <interface> -s 65535 -w <some-file> You will have to specify the correct interface and the name of a file to save into. In addition, you will have to terminate the capture with ^C when you believe you have captured enough packets. tcpdump is not part of the Wireshark distribution. You can get it from: &TcpdumpWebsite; for various platforms.

Dumpcap is a network traffic dump tool. It captures packet data from a live network and writes the packets to a file. Dumpcap's native capture file format is libpcap format, which is also the format used by Wireshark, tcpdump and various other tools. Without any options set it will use the pcap library to capture traffic from the first available network interface and write the received raw packet data, along with the packets' time stamps into a libpcap file. Packet capturing is performed with the pcap library. The capture filter syntax follows the rules of the pcap library. dumpcap -h Dumpcap 1.1.4 Capture network packets and dump them into a libpcap file. See http://www.wireshark.org for more information. Usage: dumpcap [options] ... Capture interface: -i <interface> name or idx of interface (def: first non-loopback) -f <capture filter> packet filter in libpcap filter syntax -s <snaplen> packet snapshot length (def: 65535) -p don't capture in promiscuous mode -B <buffer size> size of kernel buffer (def: 1MB) -y <link type> link layer type (def: first appropriate) -D print list of interfaces and exit -L print list of link-layer types of iface and exit -S print statistics for each interface once every second -M for -D, -L, and -S produce machine-readable output Stop conditions: -c <packet count> stop after n packets (def: infinite) -a <autostop cond.> ... duration:NUM - stop after NUM seconds filesize:NUM - stop this file after NUM KB files:NUM - stop after NUM files Output (files): -w <filename> name of file to save (def: tempfile) -b <ringbuffer opt.> ... duration:NUM - switch to next file after NUM secs filesize:NUM - switch to next file after NUM KB files:NUM - ringbuffer: replace after NUM files -n use pcapng format instead of pcap Miscellaneous: -v print version information and exit -h display this help and exit Example: dumpcap -i eth0 -a duration:60 -w output.pcap "Capture network packets from interface eth0 until 60s passed into output.pcap" Use Ctrl-C to stop capturing at any time.

Included with Wireshark is a small utility called capinfos, which is a command-line utility to print information about binary capture files. $ capinfos -h Capinfos 1.1.4 Prints information about capture files. See http://www.wireshark.org for more information. Usage: capinfos [options] <infile> ... General: -t display the capture file type -E display the capture file encapsulation Size: -c display the number of packets -s display the size of the file (in bytes) -d display the total length of all packets (in bytes) Time: -u display the capture duration (in seconds) -a display the capture start time -e display the capture end time Statistic: -y display average data rate (in bytes/sec) -i display average data rate (in bits/sec) -z display average packet size (in bytes) -x display average packet rate (in packets/sec) Miscellaneous: -h display this help and exit If no options are given the default is to display all infos

Included with Wireshark is a small utility called editcap, which is a command-line utility for working with capture files. Its main function is to remove packets from capture files, but it can also be used to convert capture files from one format to another, as well as to print information about capture files. $ editcap -h Editcap 1.1.4 Edit and/or translate the format of capture files. See http://www.wireshark.org for more information. Usage: editcap [options] ... <infile> <outfile> [ <packet#>[-<packet#>] ... ] <infile> and <outfile> must both be present. A single packet or a range of packets can be selected. Packet selection: -r keep the selected packets; default is to delete them. -A <start time> don't output packets whose timestamp is before the given time (format as YYYY-MM-DD hh:mm:ss). -B <stop time> don't output packets whose timestamp is after the given time (format as YYYY-MM-DD hh:mm:ss). Duplicate packet removal: -d remove packet if duplicate (window == 5). -D <dup window> remove packet if duplicate; configurable <dup window> Valid <dup window> values are 0 to 1000000. NOTE: A <dup window> of 0 with -v (verbose option) is useful to print MD5 hashes. -w <dup time window> remove packet if duplicate packet is found EQUAL TO OR LESS THAN <dup time window> prior to current packet. A <dup time window> is specified in relative seconds (e.g. 0.000001). NOTE: The use of the 'Duplicate packet removal' options with other editcap options except -v may not always work as expected. Specifically the -r and -t options will very likely NOT have the desired effect if combined with the -d, -D or -w. Packet manipulation: -s <snaplen> truncate each packet to max. <snaplen> bytes of data. -C <choplen> chop each packet at the end by <choplen> bytes. -t <time adjustment> adjust the timestamp of each packet; <time adjustment> is in relative seconds (e.g. -0.5). -E <error probability> set the probability (between 0.0 and 1.0 incl.) that a particular packet byte will be randomly changed. Output File(s): -c <packets per file> split the packet output to different files based on uniform packet counts with a maximum of <packets per file> each. -i <seconds per file> split the packet output to different files based on uniform time intervals with a maximum of <seconds per file> each. -F <capture type> set the output file type; default is libpcap. an empty "-F" option will list the file types. -T <encap type> set the output file encapsulation type; default is the same as the input file. an empty "-T" option will list the encapsulation types. Miscellaneous: -h display this help and exit. -v verbose output. If -v is used with any of the 'Duplicate Packet Removal' options (-d, -D or -w) then Packet lengths and MD5 hashes are printed to standard-out. $ editcap -F editcap: option requires an argument -- F editcap: The available capture file types for "F": libpcap - Wireshark/tcpdump/... - libpcap nseclibpcap - Wireshark - nanosecond libpcap modlibpcap - Modified tcpdump - libpcap nokialibpcap - Nokia tcpdump - libpcap rh6_1libpcap - RedHat 6.1 tcpdump - libpcap suse6_3libpcap - SuSE 6.3 tcpdump - libpcap 5views - Accellent 5Views capture dct2000 - Catapult DCT2000 trace (.out format) nettl - HP-UX nettl trace netmon1 - Microsoft NetMon 1.x netmon2 - Microsoft NetMon 2.x ngsniffer - NA Sniffer (DOS) ngwsniffer_1_1 - NA Sniffer (Windows) 1.1 ngwsniffer_2_0 - NA Sniffer (Windows) 2.00x niobserverv9 - Network Instruments Observer (V9) lanalyzer - Novell LANalyzer snoop - Sun snoop rf5 - Tektronix K12xx 32-bit .rf5 format visual - Visual Networks traffic capture k12text - K12 text file commview - TamoSoft CommView pcapng - Wireshark - pcapng (experimental) $ editcap -T editcap: option requires an argument -- T editcap: The available encapsulation types for "T": ether - Ethernet tr - Token Ring slip - SLIP ppp - PPP fddi - FDDI fddi-swapped - FDDI with bit-swapped MAC addresses rawip - Raw IP arcnet - ARCNET arcnet_linux - Linux ARCNET atm-rfc1483 - RFC 1483 ATM linux-atm-clip - Linux ATM CLIP lapb - LAPB atm-pdus - ATM PDUs atm-pdus-untruncated - ATM PDUs - untruncated null - NULL ascend - Lucent/Ascend access equipment isdn - ISDN ip-over-fc - RFC 2625 IP-over-Fibre Channel ppp-with-direction - PPP with Directional Info ieee-802-11 - IEEE 802.11 Wireless LAN prism - IEEE 802.11 plus Prism II monitor mode header ieee-802-11-radio - IEEE 802.11 Wireless LAN with radio information ieee-802-11-radiotap - IEEE 802.11 plus radiotap WLAN header ieee-802-11-avs - IEEE 802.11 plus AVS WLAN header linux-sll - Linux cooked-mode capture frelay - Frame Relay frelay-with-direction - Frame Relay with Directional Info chdlc - Cisco HDLC ios - Cisco IOS internal ltalk - Localtalk pflog-old - OpenBSD PF Firewall logs, pre-3.4 hhdlc - HiPath HDLC docsis - Data Over Cable Service Interface Specification cosine - CoSine L2 debug log whdlc - Wellfleet HDLC sdlc - SDLC tzsp - Tazmen sniffer protocol enc - OpenBSD enc(4) encapsulating interface pflog - OpenBSD PF Firewall logs chdlc-with-direction - Cisco HDLC with Directional Info bluetooth-h4 - Bluetooth H4 mtp2 - SS7 MTP2 mtp3 - SS7 MTP3 irda - IrDA user0 - USER 0 user1 - USER 1 user2 - USER 2 user3 - USER 3 user4 - USER 4 user5 - USER 5 user6 - USER 6 user7 - USER 7 user8 - USER 8 user9 - USER 9 user10 - USER 10 user11 - USER 11 user12 - USER 12 user13 - USER 13 user14 - USER 14 user15 - USER 15 symantec - Symantec Enterprise Firewall ap1394 - Apple IP-over-IEEE 1394 bacnet-ms-tp - BACnet MS/TP raw-icmp-nettl - Raw ICMP with nettl headers raw-icmpv6-nettl - Raw ICMPv6 with nettl headers gprs-llc - GPRS LLC juniper-atm1 - Juniper ATM1 juniper-atm2 - Juniper ATM2 redback - Redback SmartEdge rawip-nettl - Raw IP with nettl headers ether-nettl - Ethernet with nettl headers tr-nettl - Token Ring with nettl headers fddi-nettl - FDDI with nettl headers unknown-nettl - Unknown link-layer type with nettl headers mtp2-with-phdr - MTP2 with pseudoheader juniper-pppoe - Juniper PPPoE gcom-tie1 - GCOM TIE1 gcom-serial - GCOM Serial x25-nettl - X25 with nettl headers k12 - K12 protocol analyzer juniper-mlppp - Juniper MLPPP juniper-mlfr - Juniper MLFR juniper-ether - Juniper Ethernet juniper-ppp - Juniper PPP juniper-frelay - Juniper Frame-Relay juniper-chdlc - Juniper C-HDLC juniper-ggsn - Juniper GGSN lapd - LAPD dct2000 - Catapult DCT2000 ber - ASN.1 Basic Encoding Rules juniper-vp - Juniper Voice PIC usb - Raw USB packets ieee-802-16-mac-cps - IEEE 802.16 MAC Common Part Sublayer raw-telnet-nettl - Raw telnet with nettl headers usb-linux - USB packets with Linux header mpeg - MPEG ppi - Per-Packet Information header erf - Endace Record File bluetooth-h4 - Bluetooth H4 with linux header sita-wan - SITA WAN packets sccp - SS7 SCCP bluetooth-hci - Bluetooth without transport layer ipmb - Intelligent Platform Management Bus wpan - IEEE 802.15.4 Wireless PAN x2e-xoraya - X2E Xoraya flexray - FlexRay lin - Local Interconnect Network most - Media Oriented Systems Transport can20b - Controller Area Network 2.0B layer1-event - EyeSDN Layer 1 event x2e-serial - X2E serial line capture i2c - I2C wpan-nonask-phy - IEEE 802.15.4 Wireless PAN non-ASK PHY tnef - Transport-Neutral Encapsulation Format usb-linux-mmap - USB packets with Linux header and padding gsm_um - GSM Um Interface

Mergecap is a program that combines multiple saved capture files into a single output file specified by the -w argument. Mergecap knows how to read libpcap capture files, including those of tcpdump. In addition, Mergecap can read capture files from snoop (including Shomiti) and atmsnoop, LanAlyzer, Sniffer (compressed or uncompressed), Microsoft Network Monitor, AIX's iptrace, NetXray, Sniffer Pro, RADCOM's WAN/LAN analyzer, Lucent/Ascend router debug output, HP-UX's nettl, and the dump output from Toshiba's ISDN routers. There is no need to tell Mergecap what type of file you are reading; it will determine the file type by itself. Mergecap is also capable of reading any of these file formats if they are compressed using gzip. Mergecap recognizes this directly from the file; the '.gz' extension is not required for this purpose. By default, it writes the capture file in libpcap format, and writes all of the packets in the input capture files to the output file. The -F flag can be used to specify the format in which to write the capture file; it can write the file in libpcap format (standard libpcap format, a modified format used by some patched versions of libpcap, the format used by Red Hat Linux 6.1, or the format used by SuSE Linux 6.3), snoop format, uncompressed Sniffer format, Microsoft Network Monitor 1.x format, and the format used by Windows-based versions of the Sniffer software. Packets from the input files are merged in chronological order based on each frame's timestamp, unless the -a flag is specified. Mergecap assumes that frames within a single capture file are already stored in chronological order. When the -a flag is specified, packets are copied directly from each input file to the output file, independent of each frame's timestamp. If the -s flag is used to specify a snapshot length, frames in the input file with more captured data than the specified snapshot length will have only the amount of data specified by the snapshot length written to the output file. This may be useful if the program that is to read the output file cannot handle packets larger than a certain size (for example, the versions of snoop in Solaris 2.5.1 and Solaris 2.6 appear to reject Ethernet frames larger than the standard Ethernet MTU, making them incapable of handling gigabit Ethernet captures if jumbo frames were used). If the -T flag is used to specify an encapsulation type, the encapsulation type of the output capture file will be forced to the specified type, rather than being the type appropriate to the encapsulation type of the input capture file. Note that this merely forces the encapsulation type of the output file to be the specified type; the packet headers of the packets will not be translated from the encapsulation type of the input capture file to the specified encapsulation type (for example, it will not translate an Ethernet capture to an FDDI capture if an Ethernet capture is read and '-T fddi' is specified). $ mergecap -h Mergecap 1.1.4 Merge two or more capture files into one. See http://www.wireshark.org for more information. Usage: mergecap [options] -w <outfile>|- <infile> ... Output: -a concatenate rather than merge files. default is to merge based on frame timestamps. -s <snaplen> truncate packets to <snaplen> bytes of data. -w <outfile>|- set the output filename to <outfile> or '-' for stdout. -F <capture type> set the output file type; default is libpcap. an empty "-F" option will list the file types. -T <encap type> set the output file encapsulation type; default is the same as the first input file. an empty "-T" option will list the encapsulation types. Miscellaneous: -h display this help and exit. -v verbose output. A simple example merging dhcp-capture.libpcap and imap-1.libpcap into outfile.libpcap is shown below. $ mergecap -w outfile.libpcap dhcp-capture.libpcap imap-1.libpcap

There may be some occasions when you wish to convert a hex dump of some network traffic into a libpcap file. Text2pcap is a program that reads in an ASCII hex dump and writes the data described into a libpcap-style capture file. text2pcap can read hexdumps with multiple packets in them, and build a capture file of multiple packets. text2pcap is also capable of generating dummy Ethernet, IP and UDP headers, in order to build fully processable packet dumps from hexdumps of application-level data only. Text2pcap understands a hexdump of the form generated by od -A x -t x1. In other words, each byte is individually displayed and surrounded with a space. Each line begins with an offset describing the position in the file. The offset is a hex number (can also be octal - see -o), of more than two hex digits. Here is a sample dump that text2pcap can recognize: 000000 00 e0 1e a7 05 6f 00 10 ........ 000008 5a a0 b9 12 08 00 46 00 ........ 000010 03 68 00 00 00 00 0a 2e ........ 000018 ee 33 0f 19 08 7f 0f 19 ........ 000020 03 80 94 04 00 00 10 01 ........ 000028 16 a2 0a 00 03 50 00 0c ........ 000030 01 01 0f 19 03 80 11 01 ........ There is no limit on the width or number of bytes per line. Also the text dump at the end of the line is ignored. Bytes/hex numbers can be uppercase or lowercase. Any text before the offset is ignored, including email forwarding characters '>'. Any lines of text between the bytestring lines is ignored. The offsets are used to track the bytes, so offsets must be correct. Any line which has only bytes without a leading offset is ignored. An offset is recognized as being a hex number longer than two characters. Any text after the bytes is ignored (e.g. the character dump). Any hex numbers in this text are also ignored. An offset of zero is indicative of starting a new packet, so a single text file with a series of hexdumps can be converted into a packet capture with multiple packets. Multiple packets are read in with timestamps differing by one second each. In general, short of these restrictions, text2pcap is pretty liberal about reading in hexdumps and has been tested with a variety of mangled outputs (including being forwarded through email multiple times, with limited line wrap etc.) There are a couple of other special features to note. Any line where the first non-whitespace character is '#' will be ignored as a comment. Any line beginning with #TEXT2PCAP is a directive and options can be inserted after this command to be processed by text2pcap. Currently there are no directives implemented; in the future, these may be used to give more fine grained control on the dump and the way it should be processed e.g. timestamps, encapsulation type etc. Text2pcap also allows the user to read in dumps of application-level data, by inserting dummy L2, L3 and L4 headers before each packet. Possiblities include inserting headers such as Ethernet, Ethernet + IP, Ethernet + IP + UDP, or Ethernet + Ip + TCP before each packet. This allows Wireshark or any other full-packet decoder to handle these dumps. $ text2pcap -h Text2pcap 1.1.4 Generate a capture file from an ASCII hexdump of packets. See http://www.wireshark.org for more information. Usage: text2pcap [options] <infile> <outfile> where <infile> specifies input filename (use - for standard input) <outfile> specifies output filename (use - for standard output) Input: -o hex|oct|dec parse offsets as (h)ex, (o)ctal or (d)ecimal; default is hex. -t <timefmt> treats the text before the packet as a date/time code; the specified argument is a format string of the sort supported by strptime. Example: The time "10:15:14.5476" has the format code "%H:%M:%S." NOTE: The subsecond component delimiter must be given (.) but no pattern is required; the remaining number is assumed to be fractions of a second. NOTE: Date/time fields from the current date/time are used as the default for unspecified fields. Output: -l <typenum> link-layer type number; default is 1 (Ethernet). See the file net/bpf.h for list of numbers. Use this option if your dump is a complete hex dump of an encapsulated packet and you wish to specify the exact type of encapsulation. Example: -l 7 for ARCNet packets. -m <max-packet> max packet length in output; default is 64000 Prepend dummy header: -e <l3pid> prepend dummy Ethernet II header with specified L3PID (in HEX). Example: -e 0x806 to specify an ARP packet. -i <proto> prepend dummy IP header with specified IP protocol (in DECIMAL). Automatically prepends Ethernet header as well. Example: -i 46 -u <srcp>,<destp> prepend dummy UDP header with specified dest and source ports (in DECIMAL). Automatically prepends Ethernet & IP headers as well. Example: -u 1000 69 to make the packets look like TFTP/UDP packets. -T <srcp>,<destp> prepend dummy TCP header with specified dest and source ports (in DECIMAL). Automatically prepends Ethernet & IP headers as well. Example: -T 50,60 -s <srcp>,<dstp>,<tag> prepend dummy SCTP header with specified dest/source ports and verification tag (in DECIMAL). Automatically prepends Ethernet & IP headers as well. Example: -s 30,40,34 -S <srcp>,<dstp>,<ppi> prepend dummy SCTP header with specified dest/source ports and verification tag 0. Automatically prepends a dummy SCTP DATA chunk header with payload protocol identifier ppi. Example: -S 30,40,34 Miscellaneous: -h display this help and exit. -d detailed debug of parser states. -q generate no output at all (automatically turns off -d).

In an ideal world idl2wrs would be mentioned in the users guide in passing and documented in the developers guide. As the developers guide has not yet been completed it will be documented here.

As you have probably guessed from the name, idl2wrs takes a user specified IDL file and attempts to build a dissector that can decode the IDL traffic over GIOP. The resulting file is "C" code, that should compile okay as a Wireshark dissector. idl2wrs basically parses the data struct given to it by the omniidl compiler, and using the GIOP API available in packet-giop.[ch], generates get_CDR_xxx calls to decode the CORBA traffic on the wire. It consists of 4 main files. README.idl2wrs This document wireshark_be.py The main compiler backend wireshark_gen.py A helper class, that generates the C code. idl2wrs A simple shell script wrapper that the end user should use to generate the dissector from the IDL file(s).

It is important to understand what CORBA traffic looks like over GIOP/IIOP, and to help build a tool that can assist in troubleshooting CORBA interworking. This was especially the case after seeing a lot of discussions about how particular IDL types are represented inside an octet stream. I have also had comments/feedback that this tool would be good for say a CORBA class when teaching students what CORBA traffic looks like "on the wire". It is also COOL to work on a great Open Source project such as the case with "Wireshark" ( &WiresharkWebSite; )

To use the idl2wrs to generate Wireshark dissectors, you need the following: Python must be installed. See omniidl from the the omniORB package must be available. See Of course you need Wireshark installed to compile the code and tweak it if required. idl2wrs is part of the standard Wireshark distribution To use idl2wrs to generate an Wireshark dissector from an idl file use the following procedure: To write the C code to stdout. idl2wrs <your file.idl> e.g.: idl2wrs echo.idl To write to a file, just redirect the output. idl2wrs echo.idl > packet-test-idl.c You may wish to comment out the register_giop_user_module() code and that will leave you with heuristic dissection. If you don't want to use the shell script wrapper, then try steps 3 or 4 instead. To write the C code to stdout. Usage: omniidl -p ./ -b wireshark_be <your file.idl> e.g.: omniidl -p ./ -b wireshark_be echo.idl To write to a file, just redirect the output. omniidl -p ./ -b wireshark_be echo.idl > packet-test-idl.c You may wish to comment out the register_giop_user_module() code and that will leave you with heuristic dissection. Copy the resulting C code to subdirectory epan/dissectors/ inside your Wireshark source directory. cp packet-test-idl.c /dir/where/wireshark/lives/epan/dissectors/ The new dissector has to be added to Makefile.common in the same directory. Look for the declaration CLEAN_DISSECTOR_SRC and add the new dissector there. For example, CLEAN_DISSECTOR_SRC = \ packet-2dparityfec.c \ packet-3com-njack.c \ ... becomes CLEAN_DISSECTOR_SRC = \ packet-test-idl.c \ packet-2dparityfec.c \ packet-3com-njack.c \ ... For the next steps, go up to the top of your Wireshark source directory. Run configure ./configure (or ./autogen.sh) Compile the code make Good Luck !!

Exception code not generated (yet), but can be added manually. Enums not converted to symbolic values (yet), but can be added manually. Add command line options etc More I am sure :-)

See the TODO list inside packet-giop.c

The "-p ./" option passed to omniidl indicates that the wireshark_be.py and wireshark_gen.py are residing in the current directory. This may need tweaking if you place these files somewhere else. If it complains about being unable to find some modules (e.g. tempfile.py), you may want to check if PYTHONPATH is set correctly. On my Linux box, it is PYTHONPATH=/usr/lib/python2.4/