Having never done this before, I’m at a bit of a loss. I can login via telnet to our Cisco router (1721), enable it.. and look around at the access lists, but I can’t seem to figure out how to do what I need to do.
I need to basically block all traffic on port 25 (smtp) unless it comes from our exchange server (lets say it’s 192.168.1.112). I don’t know any cisco commands really.. and sort of understand the different modes (sort of), but beyond that I don’t know how to simply add in a few lines. What I have to do is this:
“First you need to create an access list describing the traffic (x.x.x.x is the ip address of the mail server)
access-list acl_out permit tcp host x.x.x.x any eq 25
access-list acl_out deny tcp any any eq 25
access-list acl_out permit ip any any
Then you need to apply that access-list to the inside interface(because it is being checked on the inside before it goes out)
access-group acl_out in interface inside”
How do I do that??