Configuring Acls; Overview; Acl Categories; Match Order - HP FlexNetwork NJ5000 User Manual

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
Basic ACLs
Advanced ACLs
Ethernet frame
header ACLs

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.
ordering uses to sort rules for each type of ACL.
Table 132 Depth-first match for ACLs
ACL category
IPv4 basic ACL
IPv4 advanced ACL
ACL number IP version
IPv4
2000 to 2999
IPv6
IPv4
3000 to 3999
IPv6
IPv4 and
4000 to 4999
IPv6
Table 132
Sequence of tie breakers
More 0s in the source IP address wildcard (more 0s means a
1.
narrower IP address range).
Smaller rule ID.
2.
Specific protocol number.
1.
More 0s in the source IP address wildcard mask.
2.
More 0s in the destination IP address wildcard.
3.
Match criteria
Source IPv4 address
Source IPv6 address
Source/destination IPv4 address, protocol number,
and other Layer 3 and Layer 4 header fields
Source/destination IPv6 address, protocol number,
and other Layer 3 and Layer 4 header fields
Layer 2 header fields, such as source and
destination MAC addresses, 802.1p priority, and
link layer protocol type
lists the sequence of tie breakers that depth-first
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