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Problem with forwarding in 35xx-XL

We have a problem with some of our 3500XL switches

for example 3512-3524XL running 12.0(5.2)XU software.

Sometimes when a new client is connected the port will

go up(the interface and line protocol)but the port is

not forwarding/receiving any packets.

No mismatch in speed and duplex,we have also tried to

clear all caches and put the port in shutdown and back.

The only way have been to reload the switch.

The interfaces is configured with vlan (switchport access

vlan x).


Community Member

Re: Problem with forwarding in 35xx-XL

Do you have portfast turned on ?

From your definition, you are saying the packet never gets forwarded, usually if the PC connected to it is using dHCP and portfast is not turned on, they never get ip address and you can't ping out or whatever.

What does the spanning tree state of the port say ?

Do you see any packets at all ? Try to use the static address.

If the above is not the case, may be you should try with the latest software version of software and open a TAC case if you still have the problem.

Community Member

Re: Problem with forwarding in 35xx-XL

We are not using DHCP, portfast is turned on and we use static IP address. It is usely firewalls or switches that is connected to the ports. The last time it was a Cisco 2924 witch was connected to ouer port in the 3524, the 2924 was taken down for some reson and when they started it up again the link went up but no traffic, i tryed shut, no shut link went down and up as expected, clear int in ouer 3524, the 2924 was rebooted nothing helped befor i rebooted ouer 3524. We ar not using spanning tree but it is not turend of in the 35xx switches and we hawe more than 63 VLANS so for every new vlan the folowing line is added in every switch "no spanning-tree vlan xxx".

Community Member

Re: Problem with forwarding in 35xx-XL

I have seen problems with this version of IOS. I upgraded to 12.0(5.3)WC(1), all problems went away.

Probably not what you wanted to hear, but worked for me.

Community Member

Re: Problem with forwarding in 35xx-XL

I run into this problem yesterday too. The version is 12.0(5.3)WC(1).

I think this is a software bug, but the problem is not easy to recreate.

Community Member

Re: Problem with forwarding in 35xx-XL

Thanks for your answer. This was not so high priority on befor but now it has hapand another time on the same port as i described first time but without any down on the port before it yust stoped forwarding but ther was input from the connected network. Are ther anyone how know about this and can tell about a fix/version witch is stabil.

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