Extended IP Access Lists
Extended IP access lists provide far more flexibility in the specification of what is to be filtered. The basic format of the extended IP access list line is
access-list access-list-number {deny|permit} protocol source source-wildcard destination destination-wildcard [precedence precedence][tostos][log]
Some of the features here are familiar, and some are new.
access-list-number, for extended IP access lists, is between 100 and 199.
protocol is a new variable that looks for a match in the protocol field of the IP packet header. The keyword choices are eigrp, gre, icmp, igmp, igrp, ip, ipinip, nos, ospf, tcp, or udp. An integer in the range 0 to 255 representing an IP protocol number may also be used. ip is a generic keyword, ...
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