Sequence numbering in ACLs

The ACEs in any ACL are sequentially numbered. In the default state, the sequence number of the first ACE in a list is "10" and subsequent ACEs are numbered in increments of 10. For example, the following show run output lists three ACEs with default numbering in a list named "My-List":
The default sequential numbering for ACEs

You can add an ACE to the end of a named or numbered ACL by using either access-list for numbered ACLs or ip access-list for named ACLs:

Adding an ACE to the end of numbered or named ACLs

For example, to append a fourth ACE to the end of the ACL in The default sequential numbering for ACEs:

Appending an ACE to an existing list

When using the access-list <1-99|100-199> <permit|deny> <SA> command to create an ACE for a numbered ACL, the ACE is always added to the end of the current list and given the appropriate sequence number. However, once a numbered list has been created, you can use the ip access-list command to open it as a named ACL and specify a nondefault sequence number, as described in the next section.