agent.circuit-id in lease file

Christian Kratzer ck-lists at
Tue Dec 13 16:22:00 UTC 2011


we have been testing ip assignment and logging based on relay agent option 82
and suboption circuit-id which our cisco access switches can specify as string.

On one Server which runs OpenSuSE 11.4 and their dhcp-server-4.2.1-0.9.1.i586 we
see following in the dhcp lease file

   option agent.circuit-id "TEST1";

when we configure following on the cisco switch with the port.

  ip dhcp snooping vlan 1 information option format-type circuit-id override string TEST1

In a second setup running FreeBSD 8 and the latest isc-dhcp42-server-4.2.3_1 port the lease file contains

   option agent.circuit-id 1:5:54:45:53:54:31;

which is basically the same in hex. Suboption 1 for circuit-id, length 5 and "TEST1" in ascii.

Seeing the circuit-id in hex makes sense when I lookup the source in server/stables.c and see
see the type specified as "X"

     static struct option agent_options[] = {
         { "circuit-id", "X",                    &agent_universe,   1, 1 },
         { "remote-id", "X",                     &agent_universe,   2, 1 },

What puzzles me ist what SuSE have done to their RPM to get the logging
in ascii and seemingly also allow matching the circuit-id in ascii.

We would like to assign fixed ips as follows:

    host test1 {
   	host-identifier option agent.circuit-id "TEST1";

but have to specify the raw hex format to get this match on the FreeBSD system:

    host test1 {
   	host-identifier option agent.circuit-id 1:5:54:45:53:54:31;

Is there a standard way to allow specifying a string for agent.circuit-id or do we have to patch our server in server/stables.c as we assume SuSE has propably done although I am unable to find the exact source rpm ?

Christian Kratzer
CK Software GmbH

Christian Kratzer                      CK Software GmbH
Email:   ck at                  Wildberger Weg 24/2
Phone:   +49 7032 893 997 - 0          D-71126 Gaeufelden
Fax:     +49 7032 893 997 - 9          HRB 245288, Amtsgericht Stuttgart
Web:         Geschaeftsfuehrer: Christian Kratzer

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