ip extended ACL

Unanswered Question
Mar 4th, 2009

When looking at one of our ACLs I sometimes see the port number after the source instead of the destination. Such as:

permit udp any eq 1434 any

What is the difference between putting the port after the source and after the destination?

I have this problem too.
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adamclarkuk_2 Wed, 03/04/2009 - 12:39

What you are matching there is

Any source IP on udp port 1434 only


Any destination IP on any udp port number

So you can see with extended ACL's you can get really granular.

Richard Burts Wed, 03/04/2009 - 14:50


The difference is whether the access list will check the source port of the packet (if you specify the port after the source address and mask) or check the destination port (if you specify the port after the destination address and mask).




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