problems pinging between FastEthernet and Ethernet interfaces

Nov 15, 2006 3 Replies

Hello,



I'm having some problems with a link between two Cisco routers. One router is a 7603 with a 48 port FastEthernet switching module and the second is a cisco 2620. The two routers are directly connected. The



7603 is using a FastEthernet interface and the 2620 is using an Ethernet interface. Both interfaces are administratively up and link protocol up. However, the routers can not ping each other. I've tried changing the duplex but haven't had any success. I have noticed that the 2620 has a valid arp table entry for the 7603 but the 7603 has an incomplete arp table entry for the 2620.

I have tested the ports and the cables and everything is working correctly when interfaced to other routers, or if the 7603 connects to the FastEthernet port on the 2620. Is there a setting I'm missing or is this a possible bug? The IOS versions are 12.2(7r) for the 2620 and



12.1(13)E6 for the 7603.

Thanks.



What routing protocol are you using? If you are using RIP, or IGRP, etc, and you do not have the correct "network" statements added, then you will not be able to ping.

Thanks

I'm running OSPF. Both routers are sitting on the same subnet and are directly connected so I don't think routing really comes into play. However, I will double check that the OSPF networks are configured correctly.

snipped-for-privacy@gmail.com wrote:

As you say, routing protocol will not matter.

Hmmm! ARP not working?

This could maybe happen if you have incorrect subnet masks configured. Maybe one is doing proxy arp and the other not.

Maybe with incorrect masks the routing protocol might matter?

The best thing is to post the config of the relevant interfaces.

Physical and VLAN.

sh run int gi 3/1 sh run int vl 1 ! for example.

People usually change real registered IP addresses In this case please do it carefully if you need to. Change only say the first octet or first and second.

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