Cisco 2651 Second Subnet

[rflanary]

I needed to open a second subnet because i ran out of IP's. I configured the second ip of 172.16.4.3 on the ethernet interface of the router as a secondary. It works great. Now some users have connectivity problems such as slowness. The other subnet is 172.16.3.0.

what could be causing the issue? Do i need to do anything to the switches?

Thanks for any help.

 

[burtsbees]

Could be duplex mismatches...post a sh int

Burt

 

[rflanary]

No i checked duplex settings.

 

[rflanary]

I can configure the clients back to static ip and they work just fine.

 

[jneiberger]

Are you saying that you already have 172.16.3.0/24 on your interface and you just added 172.16.4.0/24 to the interface?

If that's truly all you did then it will work. However, all traffic from one subnet to the other must still pass through the router even though they are physically on the same LAN.

Please post your config and your interface statistics.

 

[vipergg]

You might try on the router interface " ip route-cache same-interface" and see if that helps , this fast switches packets that came in on the interface that has to go back out that same interface. Something easy to try.

 

[burtsbees]

You said...
"I can configure the clients back to static ip and they work just fine."
I can only assume that this means when they get an IP via dhcp, that's when you have problems?

Burt

 

[rflanary]

Thanks i dont have route caching turned on. I will try that and see if it helps. The 172.16.4.0 is setup for dhcp and the other is not. How would that make on on difference?

 

[jneiberger]

vipergg is right. If you have a lot of traffic going from one of those subnets to the other, turn on same-interface route caching. That will reduce the load on the router.

Can we see the interface counters for that interface?