connectivity of 1720 to 2600 gateway

[harry]

I have a 1720 w WIC1ENET that was accessing an intermediate gateway via a Linksys to the final gateway on a leased Cisco 2600 router that gives ISP access to the internet. Ever since the intermediate Linksys was removed and the gateway and subnet mask adjusted for the the change, I have not been able to ping past the external interface of the 1720, and Cisco support has not been able to ping past the 2600. If I substitute a Linksys router for the 1720 on the local network out, I have total access to the internet, going out and coming in, Cisco can ping the Linksys. What suggestions for troubleshooting the 1720 settings? I have substituted my laptop for the Cisco going out, using appropriate gateway and IP address and subnet mask, and Cisco could not ping my laptop, yet swapping back to the Linksys brings back full connectivity. The original settings were only changed to reflect the gateway IP change and the subnet mask change. I am unable to get the router script for the 2600, due to ISP restrictions, but it has been said to be standard, with no restrictions out. Any suggestions?

[ksewnarain]

This sounds like an arp cache issue on the Cisco 2600. The Cisco 2600 has cached the Linksys MAC address and this may take up to 3hrs to time out (depending on the arp flush timer). All you have to do is reboot the 2600 router to force an arp flush while the 1720 is connected.

[harry]

Thanks for the advice. I can't believe I didn't see your message on Friday, according to your message's date and time. I can get the network engineer to reboot the 2600, so that's my next step. I would have thought that if I aliased the mac address of the original linksys router in the 1720 that the 2600 wouldn't have cared, but a reboot is an easy thing to do.