I having some difficulties configuring DHCP snooping. My network consist of 2950C-24's connected to 3550-24-FX's via fiber and the 3550-24-FX's connected to a 3750-48TS via fiber GBIC card. My DHCP server is located on the 3750 and all my workstations are on the 2950's. I can get DHCP snooping to work correctly when I directly connect the 2950 to the 3750 via trunk ethernet connection but when i try to use the 3550 is when I run into troubles. any help with this would be greatly appreciated.
Please make sure you have "ip helper-address" commands under inerfaces vlan240 & vlan252 within cat3750 to point to your DHCP server. Also please make sure your trunks are set up correctly (e.g. to autonegotiate trunking, the the interfaces must be in the same VTP domain) - I would suggest to put interfaces in trunk mode to trunk unconditionally at least for the testing purposes. As you are not using option 82 (interface tracker) your configuration should work both as configured originally and as suggested by one of the posts above.
[toc:faq]The ProblemOn traditional switches whenever we have a trunk
interface we use the VLAN tag to demultiplex the VLANs. The switch needs
to determine which MAC Address table to look in for a forwarding
decision. To do this we require the switch to do...
[toc:faq]Introduction:Netdr is a tool available on a RSP720, Sup720 or
Sup32 that allows one to capture packets on the RP or SP inband. The
netdr command can be used to capture both Tx and Rx packets in the
software switching path. This is not a substitut...
IntroductionOSPF, being a link-state protocol, allows for every router
in the network to know of every link and OSPF speaker in the entire
network. From this picture each router independently runs the Shortest
Path First (SPF) algorithm to determine the b...