Im having an issue that is causing my head to spin.
Switches: 6500 & 3750 series
Problem: We are currently in the process of replacing old printers with new ones. We are utilizing the same static IP's for the new devices as the old ones were using. When the old device is removed and the new device plugged in, the address does not ping, however the MAC table on the switch updates showing the new mac address. If the device is then changed to a different static IP it works immediatly, but when switched back to the original IP it stops working.
I have the same Problem with 2950 and 2924 Switches. A Solution would be very nice. I don`t have any Idea. The port status goes up when i switch on the printer, but ping doesn`t work. Any other static IP works.
It was clear in the description of the issue given by Derek that the issue was that the ARP table had the old MAC address (and would continue to have the old MAC address until it timed out). So the suggestion from Giuseppe was correct that clearing the ARP table was the solution. It is a little less clear in your description whether you have the same issue as Derek or not.
Perhaps it would help everyone understand this issue a little better if we clarify the difference between the switching table (frequently referred to as the MAC address table and cometimes referred to as the CAM) and the ARP table. The switching table is maintained by the switch and is used to make forwarding decisions at layer 2. The switching table updates quickly to indicate the new MAC address used by the new equipment connected to the switch port. The ARP table is maintained by the layer 3 device that is doing routing for the subnet and is used to relate an IP address to the corresponding MAC address for IP forwarding. Once an entry is learned that relates an IP address to a MAC address and put into the ARP table, then this entry stays in the ARP table for 4 hours. This produces the symptom that the new device has the same IP, has a different MAC, the new MAC shows up in the switch table, but the new device does not respond to ping - because the ARP table still has the old MAC. So clearing the ARP table is the effective way to get the new MAC into the ARP table as well as into the switching table.
Thanks for the quick replies! I cleared out the arp cache for that port on the local switch and removed the mac entries from the core switches. That seemed to have done the trick as the printer then started working.
I am wondering if the issue is not with these devices themselves. We replace plenty of other Lexmark/HP printers using the same IP's and have never had this issue. It has only been with this new brand that we just got in.
[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...