could not ping a host on same subnet

[ponparthi]

Hi

I have 1751 router with fastethernet assigned an ip of 172.20.7.88/22. Other pcs are on same subnet. I could not ping any of the host or my gateway 172.20.4.1/22. My fastethernet is up and lineprotocol is up. When I check the arp cache i see a incomplete against the ip am pinging meaning that arp is not complete. When I ping a host on the same subnet say 172.20.7.44 the pc is updating the mac add of routers fastethernet into its dynamic arp table.

I suspect this could be a hardware issue. Please confirm wether it is a hardware issue or anything related to configuration.

[Georg Pauwen]

Hello,

when IP address 172.20.7.88 is the IP address of your FastEthernet interface, that should be the default gateway of your hosts. What is IP address 172.20.4.1 used for ?

I guess you have checked if your hosts are using the right subnet mask (255.255.252.0) ?

Regards,

GP

[ponparthi]

No 172.20.4.1 is the gateway for me to go to internet which is another router.

All pcs use this as a gateway and able to ping the gateway. Iam just trying to ping the same gateway from my router with fa assigned an ip in same subnet say 172.20.7.88. Iam also not able to ping any of the host in this subnet 172.20.7.44 etc., But after i do a ping to any host my arp table shows incomplete against that ip where as the host is able to build the arp table for routers fa 's mac address.

I suspect could this be a hardware problem as I am nearing the warranty date, I need to rais an replacement request.

[Georg Pauwen]

Hello,

make sure you are using the correct source interface (FastEthernet) for your ping. Try and extended ping:

Router#ping

and specify the FastEthernet interface as your source, does that make a difference ?

Regards,

GP

[ponparthi]

Hi

I hve given try with ext ping also. This is the only interface up and connected. All other int like wan interface and bri0/0 are kept shutdown. Will the router try to route the packet on a shutdown interface. Iam not sure . Guide me if Iam wrong.

Thanks in advance

Parthiban

[Georg Pauwen]

Hello,

if all the other interfaces are shutdown, you should be ok, no routing occurs there.

How is the router connected to your subnet ? Is it connected through a switch, and is that the same switch where the hosts are connected to ? Try and use the IP address of the FastEthernet interface as the default gateway on one of your hosts, and see if you can ping that host then, and vice versa...

Regards,

GP

[suresh.krishnamurthy]

Hello Ponparti,

Change the port on the switch/hub where 1751 is connected.Also verify the existing port for any VLAN access and remove that.

Regards

Suresh Krishnamurthy