Port access security control on cisco switch 2950

Unanswered Question


Can we have the port access security control at the switch since this is like vlan extention into another side via leased line?

For example, i plug the leased into port fastethernet 20 of cisco switch 2950. How to do the port access security on port 20? Can open certain port/services on faste 20? Any examples?

I have this problem too.
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Giuseppe Larosa Mon, 08/24/2009 - 00:35

hello Swee,

if out port fas0/20 there is a remote site it may be legitimate to see multiple MAC addresses on the port and several source ip addresses.

So you need to be careful or the switch can react to legitimate users.

Port security works at OSI layer2 trying to distinguish between legitimate MAC addresses and not legitimate MAC addresses.

Hope to help


ktwaddell Mon, 08/24/2009 - 01:18


I would not put port security on a uplink, port security should be on the access ports only and therefore removing the need to place it on a uplink.

Hope this helps



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