H3C Technologies H3C SecBlade LB Cards - Manual (Page 30)

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• 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 makes sure any subset of a rule is
always matched before the rule.
Table 4 lists the sequence of tie breakers that depth-first ordering
uses to sort rules for each type of ACL.
Table 4 Sorting ACL rules in depth-first order
ACL category Sequence of tie breakers
IPv4 basic ACL
1. VPN instance
2. More 0s in the source IP address wildcard (more 0s means a narrower IP
address range)
3. Rule configured earlier
IPv4 advanced ACL
1. VPN instance
2. Specific protocol type rather than IP (IP represents any protocol over IP)
3. More 0s in the source IP address wildcard mask
4. More 0s in the destination IP address wildcard
5. Narrower TCP/UDP service port number range
6. Rule configured earlier
IPv6 basic ACL
1. VPN instance
2. Longer prefix for the source IP address (a longer prefix means a narrower IP
address range)
3. Rule configured earlier
IPv6 advanced ACL
1. VPN instance
2. Specific protocol type rather than IP (IP represents any protocol over IPv6)
3. Longer prefix for the source IPv6 address
4. Longer prefix for the destination IPv6 address
5. Narrower TCP/UDP service port number range
6. Rule configured earlier
Ethernet frame header ACL
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
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.
Rule comments and rule range remarks
Add a comment about an ACL rule to make it easy to understand. The rule comment appears below the
rule statement.
In addition, add a rule range remark to indicate the start or end of a range of rules created for the same
purpose.