PC not able to connect when in vlan

Unanswered Question
Jan 24th, 2008


I have a pc user whose pc connects to a switch. The port her pc connects to need to be put into vlan 202. However when that happens her pc cannot find the tree. As soon as I take her pc out of vlan 202 and put it into vlan1 she is able to work fine.

I have no vlan 202 and recreated the vlan but that made no difference. I also tried to plug her into another port on another switch.

They experienced a power failure and after the power was restored, this problem occurred.

Can anyone please help me?



I have this problem too.
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ankbhasi Thu, 01/24/2008 - 07:12

Hi Williem,

Can you check the output of command "show vlan" and see if vlan 202 exist there.

Also when you say cannot find the tree this means machine is not able to access the network? Is this switch a layer 2 switch or layer 3 switch?

Can you just check the routes? I believe after power failure some config would have lost and is the reason machine cannot access the network.

Check the config and see if vlan 202 is allowd on trunk ports to go to the network if this is a layer 2 switch.



*Pls rate all helpfull post

willemvwyk Thu, 01/24/2008 - 22:35

It's a layer 2 switch. C2950. Basically the port the user connects to is in vlan 202. When I check to make sure the switch can reach the default gateway I get a response. So the route to the outside world looks fine. I suspect 1 of 2 things here. Either the config has lost some settings or the vlan got corrupted. My colleague on site said the people who were in vlan 202 are not and those who are not in vlan 202 are. SO it could also be someone who unplugged cables and plugged them back into the wrong switch.

Currently I can also ping the servers from the switch.

What do you mean with "Check the config and see if vlan 202 is allowd on trunk ports to go to the network if this is a layer 2 switch"?

Thank you for your help :)


shrikar.dange Thu, 01/24/2008 - 22:45


I am not clear with this statement:

My colleague on site said the people who were in vlan 202 are not and those who are not in vlan 202 are.

for your question in above post:

issue one of the following commands

sh int (int type slot/port)(trunking interface) switchport or

sh interfaces (type slot/port) trunk or

sh running-config interface (type slot/port)

and check whether all vlans are enabled for trunking.

if possible plz post the sh run output



shri :)

willemvwyk Fri, 01/25/2008 - 02:03

Hi Shri

Thank you for the help, but I must say I am a bit lost. I have attached the run config.

There are 2 configs. The customer has a L3 switch on site which runs trunks to the switches on the separate floors. I have also included the specific switch on the first floor which is giving us problems.



ahmedchohan Fri, 01/25/2008 - 02:18

Try permit ip any any on the outbound access list and see it it solves the problem. If it does, go throught the access list to identify the issue.

willemvwyk Fri, 01/25/2008 - 02:29

All the interfaces on Layer3 switch as well as on the switch the clients connect are enabled for trunking.

Jon Marshall Fri, 01/25/2008 - 00:35


In addtion to Ankur's and Shri's points.

Where is the L3 interface for vlan 202 ie. on which switch or router.

When you say the switch can ping the default-gateway is this in vlan 1 or vlan 202. Because this is a layer 2 switch the fact that the switch can ping the default-gateway does not mean you have connectivity for vlan 202.

As Shri says, a copy of the configs would be good.


shrikar.dange Fri, 01/25/2008 - 02:23


Your configuration seems ok to me.But the ACL under vlan 202 is huge!!!! and as i dont kno your topology cant comment on it.

One more thing in one of your posts you said that some one has unplugged the cables and again plugged them in different ports. So please check the cabling.

Are you running VTP on L3 switch? your L2 switch is in transperent mode.


shri :)


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