Reminds me of this recent thread: https://puck.nether.net/pipermail/cisco-nsp/2015-August/100245.html
Frank -----Original Message----- From: cisco-nsp [mailto:cisco-nsp-boun...@puck.nether.net] On Behalf Of Markus Hauschild Sent: Thursday, August 27, 2015 6:07 AM To: cisco-nsp@puck.nether.net Subject: [c-nsp] DHCP Relay breaks after some time on Cat 3750X Hi, I have a weird problem with DHCP relay on a Cat 3750X: Configuration is as follows (full config w/o passwords in attachment): Two "ip helper-address <ip>" statements (one for each server) are set on each vlan interface where I want to have DHCP relay. After I boot the switch DHCPDISCOVER broadcasts from clients are properly forwarded to both DHCP servers (example output taken from the first one): Aug 26 17:49:57 aveta dhcpd: DHCPDISCOVER from 60:57:18:x:y:z via 172.23.4.254 Aug 26 17:49:58 aveta dhcpd: DHCPOFFER on 172.23.4.240 to 60:57:18:x:y:z ($hostname) via 172.23.4.254 Aug 26 17:49:58 aveta dhcpd: DHCPREQUEST for 172.23.4.240 (172.23.2.1) from 60:57:18:x:y:z ($hostname) via 172.23.4.254 Aug 26 17:49:58 aveta dhcpd: DHCPACK on 172.23.4.240 to 60:57:18:x:y:z ($hostname) via 172.23.4.254 Yet after a while DHCPDISCOVER broadcasts are no longer forwarded to any DHCP server, only unicast (e.g. DHCPREQUEST) still works. I had a similar config running for months (obviously a few times port/vlan assignments changed, I migrated from OSPF+OSPFv3 to OSPFv3 only ...) until I had this problem occur for the first time. The current situation is that DHCP relay works for a certain period of time (hours to days) after a cold boot until all DHCP broadcasts are silently discarded again. I do see the broadcasts on wireshark in the same VLAN, I don't see any DHCPDISCOVER on the server with tcpdump. I tried debug ip dhcp server packet but couldn't find anything helpful. Any ideas what to further debug/look into? Anything wrong with the config? Possible Hardware problem? Greetings, Markus _______________________________________________ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/