Placing Access Control Lists
Access Control Lists are used to control traffic by filtering packets and eliminating unwanted traffic on a network with a Cloud Hosting or a Website Hosting that has a Dedicated Server on it. Another important consideration of implementing ACLs is where the access list is placed. If the ACLs are placed in the proper location, not only can traffic be filtered, but it can make the whole network more efficient. If traffic is going to be filtered, the ACL should be placed where it has the greatest impact on increasing efficiency.
Suppose the enterprise policy aim is to deny telnet or FTP traffic from Router A Ethernet LAN segment to the switched Ethernet LAN Fa0/1 on Router D. At the same time, other traffic must be permitted. Several approaches can accomplish this policy. The recommended approach uses an extended ACL specifying both source and destination addresses. Place this extended ACL in Router A. Then, packets do not cross Router A’s Ethernet, do not cross the serial interfaces of Routers B and C, and do not enter Router D. Traffic with different source and destination addresses will still be permitted.