User's Manual

37-19
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 37 Configuring Network Security with ACLs
Configuring IPv4 ACLs
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_2006
Switch(config-ext-nacl)# exit
Switch(config)# ip access-list ext
ended may_access
Switch(config-ext-nacl)# permit tc
p any any time-range workhours
Switch(config-ext-nacl)# end
Switch# s
how ip access-lists
Extended IP access list lpip_default
10 permit ip any any
Extended IP access list deny_access
10 deny tcp any any time-range new_year_day_2006 (inactive)
Extended IP access list may_access
10 permit tcp any any time-range workhours (inactive)
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. Y
ou 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 acc
ess-list access-list
number remark remark global configuration command. To remove the remark, use the no form of this
command.
In this example, the workstation that belongs to Jones is allo
wed access, and the workstation that belongs
to Smith is not allowed access:
Switch(config)# access-list 1 remark Permit only Jones workstation through
Switch(config)# access-list 1 perm
it 171.69.2.88
Switch(config)# access-list 1 rema
rk Do not allow Smith through
Switch(config)# access-list 1 deny
171.69.3.13
For an entry in a named IP ACL, use the remark access-list configuration command. To remove the
remark, use the no form of this command.
In this example, the Jones subnet is not allowed to use outbound Telnet:
Switch(config)# ip access-list extended telnetting
Switch(config-ext-nacl)# remark Do
not allow Jones subnet to telnet out
Switch(config-ext-nacl)# deny tcp
host 171.69.2.88 any eq telnet
Applying an IPv4 ACL to a Terminal Line
You can use numbered ACLs to control access to one or more terminal lines. You cannot apply named
ACLs to lines. You must set identical restrictions on all the virtual terminal lines because a user can
attempt to connect to any of them.
For procedures for applying A
CLs to interfaces, see the “Applying an IPv4 ACL to an Interface” section
on page 37-20. For applying ACLs to VLANs, see the “Configuring VLAN Maps” section on
page 37-31.