Hi Ben,
thanks for your reply. I did test with dhcp-interface eth1 and dhcp-server 192.168.1.200 (which is the same IP address as eth1), but it doesn't work. I am not sure if I need a third interface on the machine sitting on the 192.168.1.0/24 network for the local DHCP server case to work, but since I don't have enough resources for this testing (the linux machine is a notebook with only 1 PCMCIA slot + 1 onboard ethernet and I already am using both interfaces), and I already have got the setup working with an external DHCP server, I'll pass on the test to later when I have time.
It should work on the loopback device provided your dhcp server is listening on it. Come to think of it, your dhcp server must listen on loopback since any local address is automatically routed via loopback. Ping your own IP address and tcpdump -i eth1 and you wont see your ICMP packets. tcpdump -i lo and you will see them. The dhcp server will likewise see the request coming in on lo rather than eth1, which if you've told it to only listen on eth1 then it will ignore them.
Assuming your DHCP server is configured to answer requests only on device lo (mine did during the originaly testing, and was ISC DHCP v3pl1 if I remember rightly), the following settings for the plugin should work:
dhcp-interface lo dhcp-relay-address 192.168.1.200 dhcp-server 127.0.0.1
Note that it is the relay address that is the most important setting - this must be a local address but not the loopback address. Also, if I remember correctly it's important that the two IP addresses are different, and it might also be necessary that the DHCP server doesn't think the relay-address belongs to itself, so don't bind it to eth1 (the problem is that DHCP servers and DHCP relays operate on the same port number so there may be a conflict between the two if they listen on the same IP address).
Sorry to be a bit vague, but it's ages since I wrote it, I've lost my test configuration and haven't got time to work on this stuff now.
I do need to test the case of the plugin working with a Win2k server DHCP server as my future use may need me to have a DHCP server being Win2k server.
It should work: it was designed with this in mind.
Regards, Ben
-- Ben McKeegan Firewall Developer Netservers.co.uk
