Issues conenction through ACL

[jameswysocki]

I have a question about ACLs. I have a 3750 switch doing base layer three routing and ACLing connections into my network from there’s on a port by port basis. Now it has become time that I need to connect to a server on the remote network.  Let’s just say I send a request to them to access port 21 they will respond on a port that will be unknown to me and the ACL would block it. What would be the best practice for this?

Thank you

[Jon Marshall]

You can either -

1) use the "established" keyword for the return traffic which works for TCP

2) use reflexive access-lists which support TCP/UDP/ICMP

3) use a stateful firewall which will automatically allow return traffic

4) write a rule in your inbound acl for the traffic eg.

access-list 101 permit tcp eq 21 any

Jon