accesslists outbounds?

[Martin Eriksson]

Hi! Found a little something in the CCNA Router and Switching Study Guide (http://www.rkingma.com/cisco/TestHome.htm). that I can't really recall reading anywhere else.. A simple scenario... s1 10.10.10.102     |     |---------------routerA---------s3 10.10.20.1     |                                                        s2 10.10.10.101 Access-list 1 permit 10.10.10.101 Access-list 1 deny 10.10.10.0 0.0.0.255 According to the text: " We could apply it as an inbound filter on Router A's interface to network 10.10.10.0, or as an outbound filter on Router A's interface to network 10.10.20.0. Outbound filters are less processor intensive for the router, so let's apply it outbound.". It's the last part I get confused with, "outbound filters are less processor intensive". I thought it was the opposite that it's better to stop the packets at the entry instead of the exit. I'm sure someone can sort things up for me.. best regards! Martin, E