Implementing Time-Based Acl Rules; Ipv4 Fragments Filtering With Acls; Configuration Guidelines; Acl Configuration Procedures - HP 830 Series Configuration Manual

Implementing time-based ACL rules

You can implement ACL rules based on the time of day by applying a time range to the rules. A
time-based ACL rule takes effect only in a time period specified by the time range.
The following types of time range are available:
• Periodic time range—Recurs periodically on a day or days of the week.
Absolute time range—Represents only a period of time and does not recur.
•

IPv4 fragments filtering with ACLs

Traditional packet filtering matches only first fragments of IPv4 packets, and allows all subsequent
non-first fragments to pass through. Attackers can fabricate non-first fragments to attack networks.
To avoid risks, the HP ACL implementation filters all fragments based on Layer 3 attributes.

Configuration guidelines

When you configure an ACL, follow these guidelines:
• You cannot add a rule with, or modify a rule to have, the same permit/deny statement as an
existing rule in the ACL.
You can only modify the existing rules of an ACL that uses the match order of config. When
•
modifying a rule of such an ACL, you may choose to change just some of the settings, in which case
the other settings remain the same.

ACL configuration procedures

IPv4 ACL configuration procedure
Step
1. Configuring a time range.
2. Adding an IPv4 ACL.
3. Configuring a rule for a basic IPv4 ACL.
4. Configuring a rule for an advanced IPv4 ACL.
5. Configuring a rule for an Ethernet frame header
ACL.
Remarks
Optional.
Add a time range. A rule referencing a time range
takes effect only during the specified time range.
Required.
Add an IPv4 ACL. The category of the added ACL
depends on the ACL number that you specify.
Required.
Complete one of the tasks according to the ACL
category.
453