Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements
Webcast-Catalyst9k
New Member

Access List - cisco 2600- HELP

Hi,

i want ask we, if the access list are bi-directional or it are one-directional?

If i want negate "LAN A" (eth1) to go in "LAB B" (eth0) which acl i must use and then "LAN B" can go to "LAN A"?

Thanks

2 REPLIES
Bronze

Re: Access List - cisco 2600- HELP

you should apply access list by the access-group command on your router ethernet interface.it's unidirectional so you can apply one for inbound connection and second for outbound connection.

Hall of Fame Super Gold

Re: Access List - cisco 2600- HELP

Emanuele

When applied on an interface access lists are uni-directional. You can apply an access list inbound on the interface and apply an access list outbound on the interface if you want a bi-directional effect.

I am not sure that I understand what you are trying to accomplish. I think that I understand that you do not want LAN A to send to LAN B. I am not clear if you want LAN B to be able to send to LAN A, which it sort of sounds like. The problem with this is how to differentiate something coming from LAN A to LAN B which is a response to something that originated from LAN B versus something originated from LAN A. For TCP connections you can use the established concept in the access list, but there is not a good way to handle UDP, ICMP, etc.

If you do not want either subnet to communicate with the other then I suggest that you write 2 access lists. The first access list would deny traffic with a source in LAN A and a destination in LAN B and would permit other traffic. This access list would be applied outbound on LAN A interface. The second access list would deny traffic with a source in LAN B and a destination in LAN A and would permit other traffic. This access list would be applied outbound on LAN B interface. If you do this I do not see a need for an inbound filter on either interface.

If I have not understood your question correctly please clarify what you are attempting to accomplish.

HTH

Rick

333
Views
0
Helpful
2
Replies
CreatePlease to create content