i need to serve DHCP requests for a given test tool tailored for a specific network hardware (hardware under test).
The testing tool (my server + simple netgear 5ports switch) seems to work as long as you pass one device at a time. When you start using 2 devices at the same time, both fail soon after the second device is plugged on the system.
Symptoms makes me think of two devices using the same IP address. Afterlooking in the wireshark trace, it seems to be exactly the case.
Those devices under test always show the same mac address : 4e:42:46:76:30:32 (NBFv02 in ascii). As a result, i think isc-dhcp-server observes that this mac adress has already been assigned a lease and serves it back to the other device.
How can i configure isc-dhcp-server so that it simply offers a new lease regardless of client mac adress?
(oberved on Ubuntu 12.04)
thanks
[edit]
i have made my own custom DHCP daemon. oh it does work. it offers leases regardless of client mac address. However, i seem to have other problems later on with ARP resolution. i am stuck
Best Answer
While what you're seeing is correct behavior, your best option will probably be either to change the client identifier in the device, or its MAC address. If the server receives a DHCPDISCOVER with the same MAC and client identifier, what other method will it have to differentiate between the machines?
On the server side you can check and see what the
duplicates
key is set to in dhcpd.conf, you should deny duplicates, and set up multiple DHCP servers(possibly withauthoritative
set to off). Then assign different pools to each server, that way the first machine will make a request to a DHCP server, and should obtain an IP, then when the next machine makes a request, the first server will ignore the request, but the second server should reply, and assign a different IP (it might be necessary to havemin sec
set to a non 0 number on the second server).The duplicates keyword
allow duplicates; deny duplicates;
P.S. this is just my understanding by reading, I've never had to deal with a situation like this personally.