HP Configuring ACLs

Configuring ACLs

Unless otherwise stated, ACLs refer to both IPv4 and IPv6 ACLs throughout this document. Grayed-out options on Web configuration pages cannot be configured.

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 essentially used for packet filtering. A packet filter drops packets that match a deny rule and permits packets that match a permit rule. ACLs are also widely used by many modules, for example, QoS and IP routing, for traffic identification.

ACL categories

Category	ACL number	IP version	Match criteria
Basic ACLs	2000 to 2999	IPv4	Source IPv4 address
		IPv6	Source IPv6 address
		IPv4	Source/destination IPv4 address, protocol number,
			and other Layer 3 and Layer 4 header fields
Advanced ACLs	3000 to 3999
		IPv6	Source/destination IPv6 address, protocol number,
			and other Layer 3 and Layer 4 header fields
Ethernet frame		IPv4 and	Layer 2 header fields, such as source and destination
	4000 to 4999		MAC addresses, 802.1p priority, and link layer
header ACLs		IPv6
			protocol type

Match order

The rules in an ACL are sorted in certain order. When a packet matches a rule, the device stops the match process and performs the action defined in the rule. If an ACL contains overlapping or conflicting rules, the matching result and action to take depend on the rule order.

The following ACL match orders are available:

•Config—Sorts ACL rules in ascending order of rule ID. A rule with a lower ID is matched before a rule with a higher ID. If you use this method, check the rule content and order carefully.

•Auto—Sorts ACL rules in depth-first order. Depth-first ordering makes sure any subset of a rule is always matched before the rule. Table 136 lists the sequence of tie breakers that depth-first ordering uses to sort rules for each type of ACL.

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