NAME¶
dhcpdump - DHCP packet dumper
SYNOPSIS¶
dhcpdump [
-h regular-expression]
-i interface
DESCRIPTION¶
This command parses the output of tcpdump 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
specifiy it as a regular expressions:
dhcpdump -i /dev/fxp0 -h ^00:c0:4f
This will display only the packets with Client Hardware Addresses which start
with 00:c0:4f.
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 incorperate 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
