Category: ACLs

Just like the numbered ACLs we’ve used so far, named ACLs allow you to filter network traffic according to various criteria. However, they have the following benefits over numbered ACLs:an ALC can be assigned a meaningful name (e.g. filter_traffic_to_server)ACL subcommands are used in the ACL configuration mode, and not in the global configuration mode as […]

To be more precise when matching a certain network traffic, extended access lists are used. Extended access lists are more difficult to configure and require more processor time than the standard access lists, but they enable a much more granular level of control.With extended access lists, you can evaluate additional packet information, such as:source and […]

To create an standard access list on a Cisco router, the following command is used from the router’s global configuration mode:R1(config)# access-list ACL_NUMBER permit|deny IP_ADDRESS WILDCARD_MASKNOTE ACL number for the standard ACLs has to be between 1–99 and 1300–1999. You can also use the host keyword to specify the host you want to permit or deny:R1(config)# […]

There are two types of access lists:1. standard access lists – with standard access lists, you can filter only on the source IP address of a packet. These types of access list are not as powerful as extended access lists, but they are less processor intensive for the router.The following example describes the way in […]

ACLs are a set of rules used most commonly to filter network traffic. They are used on network devices with packet filtering capatibilites (e.g. routers or firewalls). ACLs are applied on the interface basis to packets leaving or entering an interface.For example on how ACLs are used, consider the following network topology:Let’s say that server […]