Cisco Catalyst 2960 Series, Configuration Manual

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after the desired position had to be removed, then the new entry was added, and then all the removed entries
had to be reentered. This method was cumbersome and error prone.
This feature allows users to add sequence numbers to access list entries and resequence them. When a user
adds a new entry, the user chooses the sequence number so that it is in a desired position in the access list. If
necessary, entries currently in the access list can be resequenced to create room to insert the new entry.
Sequence Numbering Behavior
• For backward compatibility with previous releases, if entries with no sequence numbers are applied, the
first entry is assigned a sequence number of 10, and successive entries are incremented by 10. The
maximum sequence number is 2147483647. If the generated sequence number exceeds this maximum
number, the following message is displayed:
Exceeded maximum sequence number.
• If the user enters an entry without a sequence number, it is assigned a sequence number that is 10 greater
than the last sequence number in that access list and is placed at the end of the list.
• If the user enters an entry that matches an already existing entry (except for the sequence number), then
no changes are made.
• If the user enters a sequence number that is already present, the following error message is generated:
Duplicate sequence number.
• If a new access list is entered from global configuration mode, then sequence numbers for that access
list are generated automatically.
• Distributed support is provided so that the sequence numbers of entries in the Route Processor (RP) and
line card are in synchronization at all times.
• Sequence numbers are not nvgened. That is, the sequence numbers themselves are not saved. In the
event that the system is reloaded, the configured sequence numbers revert to the default sequence starting
number and increment. The function is provided for backward compatibility with software releases that
do not support sequence numbering.
• This feature works with named and numbered, standard and extended IP access lists.
Including comments in ACLs
You can use the remark keyword to include comments (remarks) about entries in any IP standard or extended
ACL. The remarks make the ACL easier for you to understand and scan. Each remark line is limited to 100
characters.
The remark can go before or after a permit or deny statement. You should be consistent about where you put
the remark so that it is clear which remark describes which permit or deny statement. For example, it would
be confusing to have some remarks before the associated permit or deny statements and some remarks after
the associated statements.
To include a comment for IP numbered standard or extended ACLs, use the access-list access-list number
remark remark global configuration command. To remove the remark, use the no form of this command.
Consolidated Platform Configuration Guide, Cisco IOS Release 15.2(4)E (Catalyst 2960-X Switches)
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Information About Configuring IPv4 Access Control Lists