problem with dhcp on 2960 switches

Hi All

I need your help

We have a dhcp server that was connected to Cisco 2960 which in turn was connected to alcatel switches, all worked fine. we changed the alcatel switches to cisco 2960's. We now have a problem that only devices directly connected to the original 2960(where the dhcp server is connected to) is receiving IP addresses we have now 4 other 2960's onthe network but we cannot get a IP address when we connect to any of the ports. doing a sniffer trace on the working switch the DHCP four way handshake is performed, discovery>>offer>>request>>>ack

On one of the other switches only the discovery is seen but no offer response from the dhcp server is seen therefore no ip address is received. the new switches only have portfast set and an ip address for vlan1 so I cannot understand what is stopping the dhcp traffic

Any Ideas



Reply to
Loading thread data ...


Check for "DHCP Snooping" on both switches. Basically, just do a "show run | inc dhcp". If you have DHCP Snooping implemented, configure uplink as a "trusted port".

Good luck,

Mike CCNP, CCDP, CCSP, Cisco Voice, MCSE W2K, MCSE+I, Security+, etc. CCIE R&S (in progress), CCIE Voice (in progress)

------ Headset Adapters for Cisco IP Phones

formatting link
formatting link

Reply to

I havn't got DHCP snooping configured on any of the switches

Reply to
SIMON WATSON Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.