When troubleshooting a problem with Access Control lists, one of the things you would want to do is to clear the counters on the ACL matches.
In Cisco IOS, you can clear the ACL Matches counters as follows:
When troubleshooting a problem with Access Control lists, one of the things you would want to do is to clear the counters on the ACL matches.
In Cisco IOS, you can clear the ACL Matches counters as follows:
With Cisco IOS version 11.2, Cisco introduced the Named ACLs. Named ACLs are Standard or Extended ACLs which are give names instead of a ACL number. Technically, other than giving a name to the ACL there isn't any other difference when it comes to the functionality as in Standard or Extended ACL.
Extended ACLs are advanced than the Standard ACLs. Unlike the Standard Access Lists where it checks only the Source IP Address to control the flow of the packets, Extended ACLs can check the
Source & Destination Address
Protocols (IP,ICMP,TCP,UDP)
Source & Destination ports
Cisco routers running Cisco IOS supports pased based IP Routing which can route packets based on a set IP Policy exiting an Interface.
Policy based routing in Cisco ROuters can be performed by using "route-map" and then applying as a policy to the interface of the IP Packets.
The route-map has a list of "match" and "set" commands where match defines the criteria under which the policy routing is performed (say, match a destination IP or a standard or Extended ACL) and set defines the actions to perform when match criteris met (say, set next hop).
ACLs in Cisco IOS can be used to control traffic flow and to use it as a simple list to define another function like NATing or Route-Maps. Standard Access List (ACL) in Cisco IOS are the simplest and oldest type of ACLs. Standard ACLs simply compare the Source IP Address on the packet against the IP Address defined on the ACL and decides whether to permit or deny the traffic as per the definition in the ACL.
When used to control traffic, it is recommended that the ACLs in general are applied to the interface closest to the segment where the traffic originates.