Unanswered Question
Sep 28th, 2009

Hi Friends,

I have query regarding implementation of access list on a physical interface or on a vlan interface. Mean to say what is the difference in applying acl on (in).


I have this problem too.
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lamav Mon, 09/28/2009 - 20:22

An access-list applied outbound to a vlan interface is traffic going TO machines on that vlan.

An access-list applied inbound to a vlan is traffic coming FROM machines on that vlan.

sharma16031981 Mon, 09/28/2009 - 22:02

could you please tell me where will be the source and destination in both cases.

platinum_jem Mon, 09/28/2009 - 22:14

Take this for example.

You have a interface VLAN 10 and hosts in this VLAN

When you use this host to access other network, it will be the IN direction at interface VLAN 10

When host from other network access to this host , it will be the OUT direction at interface VLAN 10

Try to think of the direction of traffic with respect to the Interface itself.

IN Direction (IN to the interface)

Host --> Interface VLAN 10

OUT Direction (OUT from the interface)

Host <-- Interface VLAN 10

platinum_jem Mon, 09/28/2009 - 20:23

If you are querying about direction-wise,

IN = Traffic from the VLAN going out

OUT = Traffic going towards the VLAN


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