Access-group but no access-list

[kgraham]

I have come across a scenario that I have been searching for some reference material.

An access-group is applied to an interface(in), but there is no access-list configured.

On one side, someone has mentioned to me that the access-list is implied and that a deny all would occur. The interface has both inbound and outbound traffic. Thus I do not believe this answer.

On the other side it looks as if there was an access-list configured on the router and then was removed without removing the access-group. Thus negating the access-group to a non-functioning entry in the router configuration.

Can anyone please point me in the right direction. "gut" feeling leans me towards the access-group being a non-functioning entity.

Any assistance would be appreciated.

version 12.0(7)T

Kim

[rsissons]

I believe this depends on what level of IOS you are running. Older IOS would use the implicit deny as the default for a missing access list so all traffic would be denied leading to the potential to lock yourself out quite easily when doing changes remotely.

However, this was changed at some point to allow all traffic.

[kgraham]

I will start my digging for the change point over the weekend. It sticks in my mind that I have read something about it but need to find it so I can take it out of the "questions to answer" side of things. Thanks for your time.

Kim

[dmallyon]

Your right Kim, there is no such thing as an "implied" access-list.

The access-group command is how an access list is enabled either inbound or outbound on an interface.