Review on Internet Usage Control Using Access Control Techniques

Abstract

The contact list is a group of statements. Each statement defines a pattern that would be found in an IP packet. As each packet comes through an interface with an associated access list, the list is scanned from top to bottom in the exact order that it was entered—for a pattern that matches the incoming packet. Access list criteria could be the source address of the traffic, the destination address of the traffic, the upper-layer protocol, or other information .Cisco provides basic traffic filtering capabilities with access control lists .Access lists can be configured for all routed network protocols (IP, AppleTalk, and so on) to filter the packets of those protocols as the packets pass through a router. When creating an access list, you define criteria that are applied to each packet that is processed by the router; the router decides whether to forward or block each packet on the basis of whether or not the packet matches the criteria. Typical criteria you define in access lists are packet source addresses, packet purpose addresses, and upper-layer protocol of the packet. However, each protocol has its own specific set of criteria that can be clear. For a single access list, you can define multiple criteria in multiple, separate access list statements. Each of these statements should reference the same identifying name or number, to tie the statements to the same access list. You can have as many criteria statements as you want, limited only by the available memory. Of course, the more statements you have, the more hard it will be to comprehend and manage your access lists. Placement and understanding of the traffic flow is important to understand up front before you configure an ACL on a router interface.