We have just encountered a DHCP problem involving clients attached to Cat4006 access layer switches. The distribution layer is Cat6509.
Clients on one particular VLAN suddenly cannot obtain DHCP address. Static client cannot ping virtual HSRP default gateway address, but can ping out past it!! Trace on VLAN when performing DHCP request shows only DHCPDISCOVER packets arriving at VLAN interface on distribution MSFC......the packets are not being forwarded using IP Helper address to third party DHCP service provider. All other VLANs work OK.
[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...