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24-17
Catalyst 2950 Desktop Switch Software Configuration Guide
78-11380-05
Chapter 24 Configuring Network Security with ACLs
Configuring ACLs
deny tcp any any time-range new_year_day_2000 (inactive)
deny tcp any any time-range thanskgiving_2000 (active)
deny tcp any any time-range christmas_2000 (inactive)
permit tcp any any time-range workhours (inactive)
This example uses named ACLs to permit and deny the same traffic.
Switch(config)# ip access-list extended deny_access
Switch(config-ext-nacl)# deny tcp any any time-range new_year_day_2000
Switch(config-ext-nacl)# deny tcp any any time-range thanksgiving_2000
Switch(config-ext-nacl)# deny tcp any any time-range christmas_2000
Switch(config-ext-nacl)# exit
Switch(config)# ip access-list extended may_access
Switch(config-ext-nacl)# permit tcp any any time-range workhours
Switch(config-ext-nacl)# end
Switch# show ip access-lists
Extended IP access list deny_access
deny tcp any any time-range new_year_day_2000 (inactive)
deny tcp any any time-range thanksgiving_2000 (inactive)
deny tcp any any time-range christmas_2000 (inactive)
Extended IP access list may_access
permit tcp any any time-range workhours (inactive)
Including Comments About Entries in ACLs
You can use the remark command 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.
For IP numbered standard or extended ACLs, use the access-list access-list number remark remark
global configuration command to include a comment about an access list. To remove the remark, use the
no form of this command.
In this example, the workstation belonging to Jones is allowed access, and the workstation belonging to
Smith is not allowed access:
Switch(config)# access-list 1 remark Permit only Jones workstation through
Switch(config)# access-list 1 permit 171.69.2.88
Switch(config)# access-list 1 remark Do not allow Smith workstation through
Switch(config)# access-list 1 deny 171.69.3.13
For an entry in a named IP ACL, use the remark access-list global configuration command. To remove
the remark, use the no form of this command.