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You can also add a rule range remark to indicate the start or end of a range of rules created for the
same purpose. A rule range remark always appears above the specified ACL rule. If the specified
rule has not been created yet, the position of the comment in the ACL is as follows:
•
If the match order is config, the remark is inserted into the ACL in descending order of rule ID.
•
If the match order is auto, the remark is placed at the end of the ACL. After you create the rule,
the remark appears above the rule.
For more information about how to use rule range remarks, see the rule remark command in ACL
and QoS Command Reference for your device.
ACL rule numbering
What is the ACL rule numbering step
If you do not assign an ID to the rule you are creating, the system automatically assigns it a rule ID.
The rule numbering step sets the increment by which the system automatically numbers rules. For
example, the default ACL rule numbering step is 5. If you do not assign IDs to rules you are creating,
they are automatically numbered 0, 5, 10, 15, and so on. The wider the numbering step, the more
rules you can insert between two rules.
By introducing a gap between rules rather than contiguously numbering rules, you have the flexibility
of inserting rules in an ACL. This feature is important for a config order ACL, where ACL rules are
matched in ascending order of rule ID.
Automatic rule numbering and renumbering
The ID automatically assigned to an ACL rule takes the nearest higher multiple of the numbering step
to the current highest rule ID, starting with 0.
For example, if the numbering step is 5 (the default), and there are five ACL rules numbered 0, 5, 9,
10, and 12, the newly defined rule is numbered 15. If the ACL does not contain any rule, the first rule
is numbered 0.
Whenever the step changes, the rules are renumbered, starting from 0. For example, if there are five
rules numbered 5, 10, 13, 15, and 20, changing the step from 5 to 2 causes the rules to be
renumbered 0, 2, 4, 6, and 8.
Fragments filtering with ACLs
Traditional packet filtering matches only first fragments of packets, and allows all subsequent
non-first fragments to pass through. Attackers can fabricate non-first fragments to attack networks.
To avoid the risks, the HPE ACL implementation:
•
Filters all fragments by default, including non-first fragments.
•
Allows for matching criteria modification, for example, filters non-first fragments only.
ACL configuration task list
Task
Configuring a time range
Configuring a basic ACL
Configuring an advanced ACL
Configuring an Ethernet frame header ACL
Remarks
Optional.
Applicable to IPv4 and IPv6 ACLs.
Required.
Configure at least one task.
Applicable to IPv4 and IPv6 except that simple ACLs
are for IPv6.
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