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IPv6 basic or advanced ACL, its ACL number and name must be unique 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 specific 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 approach, carefully check the rules and their order.
•
auto—Sorts ACL rules in depth-first order. Depth-first ordering guarantees that any subset of a
rule is always matched before the rule.
ordering uses to sort rules for each type of ACL.
Table 1 Sort ACL rules in depth-first order
ACL category
IPv4 basic ACL
IPv4 advanced ACL
IPv6 basic ACL
IPv6 advanced ACL
Ethernet frame header ACL
A wildcard mask, also called an inverse mask, is a 32-bit binary and represented in dotted decimal
notation. In contrast to a network mask, the 0 bits in a wildcard mask represent "do care" bits, and the
1 bits represent "don't care" bits. If the "do care" bits in an IP address are identical to the "do care"
bits in an IP address criterion, the IP address matches the criterion. All "don't care" bits are ignored.
The 0s and 1s in a wildcard mask can be noncontiguous. For example, 0.255.0.255 is a valid
wildcard mask
ACL rule comments and rule range remarks
You can add a comment about an ACL rule to make it easy to understand. The rule comment
appears below the rule statement.
Table 1
Sequence of tie breakers
1.
More 0s in the source IP address wildcard (more 0s means a narrower
IP address range).
2.
Rule configured earlier.
1.
Specific protocol type rather than IP (IP represents any protocol over IP).
2.
More 0s in the source IP address wildcard mask.
3.
More 0s in the destination IP address wildcard.
4.
Narrower TCP/UDP service port number range.
5.
Rule configured earlier.
1.
Longer prefix for the source IP address (a longer prefix means a
narrower IP address range).
2.
Rule configured earlier.
1.
Specific protocol type rather than IP (IP represents any protocol over
IPv6).
2.
Longer prefix for the source IPv6 address.
3.
Longer prefix for the destination IPv6 address.
4.
Narrower TCP/UDP service port number range.
5.
Rule configured earlier.
1.
More 1s in the source MAC address mask (more 1s means a smaller
MAC address).
2.
More 1s in the destination MAC address mask.
3.
Rule configured earlier.
2
lists the sequence of tie breakers that depth-first
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