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New Member

Strange VLAN Behaviour

Hi Folks,

Appreciate any help on a Vlan issue.

Basically have a vlan configured on a MSFC

Have a number of machines connected to switchports in this vlan. When we power up the machines they can not connect to anything outside the vlan. Machines get IP's via a helper address and can ping the default vlan gateway. After roughly 15-20 minutes, comnnections are allowed out. I have no ACL blocking in place. This happens everytime we power the machines down for a while and restart. There is nothing local on the machines blocking connections (firewall,AV), I have tried various builds and it makes no difference. The switchports are only configured for access to the said vlan. There is no issue with spantree or portfast settings. Help


Re: Strange VLAN Behaviour

Are you using port security on that VLAN?

Also: check the consistency of the MST-VLAN mapping on all the switches you have, and check the VLANs allowed on each of the trunks - they should correspond to whole sets of MST instances, nothing less, nothing more.

Kevin Dorrell


New Member

Re: Strange VLAN Behaviour

Not using port security, using an old version of catos on the 6500, doesn't have the spantree mst command

Re: Strange VLAN Behaviour

I'm sorry. What on earth made me think we were dealing with MST? It must be Friday again!