Problem with DHCP relay

RouterOS General
1

Hi all,
I have got problem with DHCP relay. MT is configured as a DHCP server.
But. I have got switches with layer 3 function and two vlans (two interfaces). I made DHCP relaying on switch to MT. I see some packets in sniffer on port 67 (UDP) when client is requesting … but MT doesn´t offer IP.
In the same case, but DHCP server is LINUX, everything is OK.
Testing on MT version 2.9.8 to 2.9.25 :slight_smile:
Any ideas? Thanks

2

Turn on DHCP logging on the MT and post the log here for a failed DHCP request.

Regards

Andrew

3

Thanks for reply. But nothing is in the log about this (debug logging is enabled).
:slight_smile: It looks like, that MT doesn´t receive DHCP relayed requests.
Switches are 3COM SS III 3226 …

4

In this case, you need to check if the MT even receives the packets. Is it listening on the IP address that the DHCP relay is configured with? Can you ping the MT from the switch command line etc.

Regards

Andrew

5

Everything is OK. Really :slight_smile: If I changed MT to LINUX. Relayed DHCP worked good …

6

I have the same problem. but it is a CMTS ackting as DHCP relay

7

What is CMTS ackting? :slight_smile:

8

the CMTS is working as DHCP relay