NAME

       dhcpdump - DHCP packet dumper

SYNOPSIS

       dhcpdump [-h regular-expression] [-H] -i interface

       dhcpdump [-h regular-expression] [-H] -r pcapfile

DESCRIPTION

       This command listens on a network interface to display the dhcp-packets for easier
       checking and debugging.

USAGE

       dhcpdump -i /dev/fxp0

       If you want to filter a specific Client Hardware Address (CHADDR), then you can specify it
       as a regular expression:

       dhcpdump -i /dev/fxp0 -h ^00:c0:4f

       This will display only the packets with Client Hardware Addresses which start with
       00:c0:4f.

       Option -H will additionally show full packet hex dump.

       Instead of getting live data from an interface, a pcap dump file can be used:

       dhcpdump -r pcapfile

OUTPUT

         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)

       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.

RETURN VALUES

       Always 0.

NOTES

       Privileged access is often needed for accessing the interface.

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.

THANKS TO

       Ralph Droms and Ted Lemons "The DHCP Handbook", ISBN 1-57870-137-6.

       Peter Apian-Bennewitz <apian@ise.fhg.de> for his Client Hardware Address filtering

AUTHOR

       Edwin Groothuis, edwin@mavetju.org (http://www.mavetju.org)

SEE ALSO

       dhcpd(8), tcpdump(1), RFC2132