NAME

ipgrab - A Verbose Packet Sniffer

SYNOPSIS

ipgrab [ -ablmnPprTtwx ] [ -c cnt ] [ -i if ] [ expr ]

DESCRIPTION

ipgrab reads and parses packets from the link layer through the application layer, dumping explicit header information along the way. It is a lot like tcpdump except that it prints almost every header field.

Options

-a: Do not display application layer data.
-b: Buffer standard output. Useful when you're redirecting output to a file.
-c cnt, --count cnt: Terminate after receiving cnt packets.
-C proto, --CCP proto: Assume a particular CCP protocol, such as MPPC. MPPC is the only one supported as yet.
-d: Dump extra padding in packets. For example, according to an IP header, the packet ends at a certain point, but the link layer may have padded it beyond that. This option displays the padding. Not valid in minimal mode.
-h, --help: Display usage screen with a brief description of the command line options.
-i if, --interface if: Makes ipgrab listen to packets on interface if, e.g., eth0. If this option is not used, the default interface will be assumed.
-l: Don't display link-layer headers. The following protocols are considered to be link layer: ARP, CHAP, Ethernet, IPCP, LCP, LLC, Loopback, PPP, PPPoE, Raw, Slip.
-m: Minimal mode output. When operating in this mode, ipgrab displays only brief header information.
-n: Don't display network-layer headers. The following protocols are considered to be network layer: AH, ESP, GRE, ICMP, ICMPv6, IGMP, IP, IPv6, IPX, IPXRIP.
-P string: Initiate a dynamic port mapping. This option must be followed by a string of the form `<protocol>=<port>', such as `http=8080'.
-p: Dump packet payloads beyond what IPgrab parses. In other words, if IPgrab does not parse a particular application, this option will dump application data in hex and text format.
-r FILE: Read packets from a file, rather than an interface. The file shoule be created in "raw" format, such as with '-w' option.
-T: Do not display timestamps in minimal mode.
-t: Don't display transport layer headers. The following protocols are considered to be transport layer: SPX, TCP, UDP.
-v, --version: Display version number and then quit.
-w FILE: Write the raw packets to a file, rather than the screen. The packets will not be parsed. The file can be read with the '-r' option.
-x: Hex dump mode. After processing each layer, dump out the contents of that layer in hex and text. Only valid in main mode.
expr: Berkeley packet filter expression. See tcpdump(8) man page for details and examples.

NOTES

Requires libpcap version 0.3 or greater to be installed.

AUTHOR