H3C Technologies H3C S7500E Series Switches - Manual (Page 13)

1-3
Category ACL number IP version Match criteria
IPv6
Source/destination IPv6 address, protocols
over IPv6, 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
ACL Numbering and Naming
Each ACL category has a unique range of ACL numbers. When creating an ACL, you must assign it a
number for identification, and in addition, you can also assign the ACL a name for the ease of
identification. After creating an ACL with a name, you can neither rename it nor delete its name.
For an Ethernet frame header ACL, the ACL number and name must be globally unique. For an IPv4
basic or advanced ACLs, its ACL number and name must be unique among all IPv4 ACLs, and for an
IPv6 basic or advanced ACL, among all IPv6 ACLs. You can assign an IPv4 ACL and an IPv6 ACL the
same number and name.
Match Order
The rules in an ACL are sorted in a 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.
Two ACL match orders are available:
z 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 approach, check the rules and their order carefully.
z auto: Sorts ACL rules in depth-first order, as described in Table 1-2 . The depth-first order varies
with ACL categories.
Table 1-2 Sorting ACL rules in depth-first order
ACL category Depth-first rule sorting procedures
IPv4 basic ACL
1) A rule configured with a VPN instance takes precedence.
2) A rule with more 0s in the source IP address wildcard mask takes precedence.
More 0s means a narrower IP address range.
3) A rule with a smaller ID takes precedence.