Problem with cisco VLAN - 2960 switch

Sep 04, 2012 2 Replies

Hello,



We have a small network (/28 mask) with two PC's and manually configured IP's.



PC's are connected to the 2960 switch on two VLAN ports to allow only two PC's at a time on this VLAN. This switch is trunked to a 1800 series router.



The problem is, if we remove a PC and try to connect another different PC with the same IP, the PC will not work unless the switch is reset.



Question - Is there a way to automate this so the switch does not have to be touched each time a new PC is connected?



Thanks.


at a time on this VLAN. This switch is trunked to a 1800 series router.

Interesting odd setup.

the same IP, the PC will not work unless the switch is reset.

touched each time a new PC is connected?

Most likely you have an ARP cache issue. In your little setup, resetting the ARP cache timer downwards to a minute or so shouldn't cause any issue, and then you may just have to wait a minute after you change the IP address on a machine.

Or login to the switch and "clear arp".

PC's at a time on this VLAN. This switch is trunked to a 1800 series router.

with the same IP, the PC will not work unless the switch is reset.

touched each time a new PC is connected?

Thanks for the quick response Doug.

Yes...this is a unique network aboard a ship at sea and resources are limited because of satellite communications.

I actually was just about to set the arp timeout and saw your response. Give me more confidence now:)

Seems this can be set on the router and the switch for this VLAN. I set both for now.

Thanks again!

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