.\" -*- mode: troff; coding: utf-8 -*- .\" Automatically generated by Pod::Man 5.01 (Pod::Simple 3.43) .\" .\" Standard preamble: .\" ======================================================================== .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>. .ie n \{\ . ds C` "" . ds C' "" 'br\} .el\{\ . ds C` . ds C' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is >0, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .\" .\" Avoid warning from groff about undefined register 'F'. .de IX .. .nr rF 0 .if \n(.g .if rF .nr rF 1 .if (\n(rF:(\n(.g==0)) \{\ . if \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . if !\nF==2 \{\ . nr % 0 . nr F 2 . \} . \} .\} .rr rF .\" ======================================================================== .\" .IX Title "DHCPDUMP 8" .TH DHCPDUMP 8 "23 June 2008" "perl v5.38.2" "User Contributed Software" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH NAME dhcpdump \- DHCP packet dumper .SH SYNOPSIS .IX Header "SYNOPSIS" \&\fBdhcpdump\fR [\fB\-h\fR \fIregular-expression\fR] [\fB\-H\fR] \fB\-i\fR \fIinterface\fR .PP \&\fBdhcpdump\fR [\fB\-h\fR \fIregular-expression\fR] [\fB\-H\fR] \fB\-r\fR \fIpcapfile\fR .SH DESCRIPTION .IX Header "DESCRIPTION" This command listens on a network interface to display the dhcp-packets for easier checking and debugging. .SH USAGE .IX Header "USAGE" dhcpdump\ \-i\ /dev/fxp0 .PP If you want to filter a specific Client Hardware Address (CHADDR), then you can specify it as a regular expression: .PP dhcpdump\ \-i\ /dev/fxp0\ \-h\ ^00:c0:4f .PP This will display only the packets with Client Hardware Addresses which start with 00:c0:4f. .PP Option \fB\-H\fR will additionally show full packet hex dump. .PP Instead of getting live data from an interface, a pcap dump file can be used: .PP dhcpdump\ \-r\ pcapfile .SH OUTPUT .IX Header "OUTPUT" .Vb 10 \& TIME: 15:45:02.084272 \& IP: 0.0.0.0.68 (0:c0:4f:82:ac:7f) > 255.255.255.255.67 (ff:ff:ff:ff:ff:ff) \& OP: 1 (BOOTPREQUEST) \& HTYPE: 1 (Ethernet) \& HLEN: 6 \& HOPS: 0 \& XID: 28f61b03 \& SECS: 0 \& FLAGS: 0 \&CIADDR: 0.0.0.0 \&YIADDR: 0.0.0.0 \&SIADDR: 0.0.0.0 \&GIADDR: 0.0.0.0 \&CHADDR: 00:c0:4f:82:ac:7f:00:00:00:00:00:00:00:00:00:00 \& SNAME: . \& FNAME: . \&OPTION: 53 ( 1) DHCP message type 3 (DHCPREQUEST) \&OPTION: 54 ( 4) Server identifier 130.139.64.101 \&OPTION: 50 ( 4) Request IP address 130.139.64.143 \&OPTION: 55 ( 7) Parameter Request List 1 (Subnet mask) \& 3 (Routers) \& 58 (T1) \& 59 (T2) .Ve .PP At the option field, the first field is the value of the option, the second one (between brackets) is the length of the option-datafield, the third field is the name of the option, the fourth field is the data of the option. .SH "RETURN VALUES" .IX Header "RETURN VALUES" Always 0. .SH NOTES .IX Header "NOTES" Privileged access is often needed for accessing the interface. .SH BUGS .IX Header "BUGS" Not all the parameter options are printed verbose, because of lack of documentation. Not all the options are tested, because of lack of clients/servers with these options. If you have a dump of one of them, please send them to me and I'll incorporate them. .SH "THANKS TO" .IX Header "THANKS TO" Ralph Droms and Ted Lemons "The DHCP Handbook", ISBN 1\-57870\-137\-6. .PP Peter Apian-Bennewitz for his Client Hardware Address filtering .SH AUTHOR .IX Header "AUTHOR" Edwin Groothuis, edwin@mavetju.org (http://www.mavetju.org) .SH "SEE ALSO" .IX Header "SEE ALSO" \&\fBdhcpd\fR\|(8), \fBtcpdump\fR\|(1), RFC2132