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28-16
Catalyst 2960 Switch Software Configuration Guide
78-16881-01
Chapter 28 Configuring Network Security with ACLs
Configuring IPv4 ACLs
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.
In this example, the workstation that belongs to Jones is allowed 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 permit 171.69.2.88
Switch(config)# access-list 1 remark 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 ACLs to interfaces, see the “Applying an IPv4 ACL to an Interface” section
on page 28-17.
Beginning in privileged EXEC mode, follow these steps to restrict incoming and outgoing connections
between a virtual terminal line and the addresses in an ACL:
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
line [console | vty] line-number Identify a specific line to configure, and enter in-line configuration mode.
• console—Specify the console terminal line. The console port is DCE.
• vty—Specify a virtual terminal for remote console access.
The line-number is the first line number in a contiguous group that you want
to configure when the line type is specified. The range is from 0 to 16.
Step 3
access-class access-list-number
{in | out}
Restrict incoming and outgoing connections between a particular virtual
terminal line (into a device) and the addresses in an access list.
Step 4
end Return to privileged EXEC mode.
Step 5
show running-config Display the access list configuration.
Step 6
copy running-config startup-config (Optional) Save your entries in the configuration file.