1
Configuring ACLs
Overview
An access control list (ACL) is a set of rules (or permit or deny statements) for identifying traffic
based on criteria such as source IP address, destination IP address, and port number.
ACLs are primarily used for packet filtering. "Configuring packet filtering with ACLs" p
rovides an
example. You can use ACLs in QoS, security, routing, and other feature modules for identifying traffic.
The packet drop or forwarding decisions depend on the modules that use ACLs.
Applications on the switch
An ACL is implemented in hardware or software, depending on the module that uses it.
• If the module is implemented in hardware (for example, the packet filter or QoS module), the
ACL is applied to hardware to process traffic.
• If the module is implemented in software (for example, the routing module or the login
management module), the ACL is applied to software to process traffic.
The Telnet and SNMP features in the login management module denies packets that do not match
any ACL. Some modules (QoS for example) ignore the permit or deny action in ACL rules and do not
base their drop or forwarding decisions on the action set in ACL rules. See the specified module for
information about ACL application.
ACL categories
Category ACL number IP version Match criteria
Basic ACLs 2000 to 2999
IPv4 Source IPv4 address.
IPv6 Source IPv6 address.
Advanced ACLs 3000 to 3999
IPv4
Source IPv4 address, destination IPv4
address, packet priority, protocol number, and
other Layer 3 and Layer 4 header fields.
IPv6
Source IPv6 address, destination IPv6
address, packet priority, protocol number, and
other Layer 3 and Layer 4 header fields.
Ethernet frame
header ACLs
4000 to 4999 IPv4 and IPv6
Layer 2 header fields, such as source and
destination MAC addresses, 802.1p priority,
and link layer protocol type.
Numbering and naming ACLs
Each ACL category has a unique range of ACL numbers. When creating an ACL, you must assign it
a number. In addition, you can assign the ACL a name for ease of identification. After creating an
ACL with a name, you cannot rename it or delete its name.
For an IPv4 basic or advanced ACLs, its ACL number and name must be unique in IPv4. For an IPv6
basic or advanced ACL, its ACL number and name must be unique in IPv6.
To Next Page
Loading...
Need help?
General