Fragments Filtering With Acls; Configuration Task List; Configuring A Basic Acl - HP MSR4080 Configuration Manual

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 HP ACL implementation does the follows:
Filters all fragments by default, including non-first fragments.
•
Allows for matching criteria modification, for example, filters non-first fragments only.
•

Configuration task list

Tasks at a glance
(Required.) Perform at least one of the following tasks:
•

Configuring a basic ACL

Configuring an IPv4 basic ACL
Configuring an IPv6 basic ACL
•
Configuring an advanced ACL
Configuring an IPv4 advanced ACL
Configuring an IPv6 advanced ACL
•
Configuring an Ethernet frame header ACL
(Optional.)
(Optional.)
Configuring a basic ACL
This section describes procedures for configuring IPv4 and IPv6 basic ACLs.
Copying an ACL
Configuring packet filtering with ACLs
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