[c-nsp] DHCP Forwarding Strategy

[Markus H]

I've just read the Option 82 topic which brings to memory an unsolved
prolbem I had:

The "current" state of a network for a rather small event:
At the core a Cisco 3550, a few 2950s and non-Cisco WLAN APs (the APs
just map a few SSIDs onto the corresponding VLANs with either no
encryption (guest) or WPA2 (event organziers)).
The DHCP Server (dnsmasq) is a VM which has an interface for every
VLAN where DHCP leases are needed (that would be all except the
management VLAN für the ciscos and APs).

What I would like it to be:
The 3550 forwards DHCP requests to the DHCP VM. The VM decides (based
on which VLAN the client is in) from which pool to give out an address
and needs only one interface/ip. Further benefit: the VM server needs
to deal with fewer VMs and gets a much more simple config.

The Problem:
As I understand Option 82 won't help, because port numbers on the
cisco are not of much use in my case. And I haven't found a way to map
the forwarded request onto a VLAN or subnet.


So is there anything I am missing? Is there any good documentation on
what information forwarded DHCP requests have by default or what
things I can add (besides the quite useless port number where the
request came in)?

Greetings,
Markus