Access Control List

I am studying for my ccna exam but I have difficulty understanding how to create them as well as configure them I have tried packet tracer but it wants me to configure named list I can't get the basic ones right. PLEASE HELP ANY ONE :

What is an example of how you are doing it wrong?

When Creating ACL's you need to first know, what traffic you want to allow and what you want to block

A router handles access-lists based on the way you configure them


For example if you need to block ftp access, to a particular n/w ,

you need to first mention the deny statement and then a permit for the rest of the traffic to flow.

For the above example , if you first permit everything and then deny ftp , the router is going to allow all the traffic as it compares the packets to the first statement in the acl list.

Keep always in mind that there is an implicit deny at the end of the acl


Applying these acl's to an interface: Understand on how packets are flowing, in or out from that interface and bind the acl's to that interface accordingly.
example: If traffic is entering in to ethernet interface , and you need an acl on the traffic entering inside, bind the acl inside.


I hope this should help you.......

Quite well explained Skepticles. The main thingy behind these ACLS is the direction of the traffic that you want to apply it. One normally knows the type of traffic that has to be blocked or allowed, but direction and the interface to apply it on, that requires understanding the nature of the traffic and network.

Oops !! sorry, the great reply was from emperorz.

Simple mistake, we look the same