Cisco Catalyst 3550 series Software Configuration Manual page 554

Configuring IP ACLs
Beginning in privileged EXEC mode, follow these steps to create an extended ACL using names:
Command
Step 1
configure terminal
Step 2
ip access-list extended name
Step 3
{deny | permit} protocol {source
[source-wildcard] | host source | any}
{destination [destination-wildcard] | host
destination | any} [precedence precedence]
[tos tos] [established] [log] [time-range
time-range-name]
Step 4
end
Step 5 show access-lists [number | name]
Step 6
copy running-config startup-config
To remove a named extended ACL, use the no ip access-list extended name global configuration
command.
When you are creating standard extended ACLs, remember that, by default, the end of the ACL contains
an implicit deny statement for everything if it did not find a match before reaching the end. For standard
ACLs, if you omit the mask from an associated IP host address access list specification, 0.0.0.0 is
assumed to be the mask.
After you create an ACL, any additions are placed at the end of the list. You cannot selectively add ACL
entries to a specific ACL. However, you can use no permit and no deny access-list configuration mode
commands to remove entries from a named ACL. This example shows how you can delete individual
ACEs from the named access list border-list:
Switch(config)# ip access-list extended border-list
Switch(config-ext-nacl)# no permit ip host 10.1.1.3 any
Being able to selectively remove lines from a named ACL is one reason you might use named ACLs
instead of numbered ACLs.
After creating an ACL, you must apply it to a line or interface, as described in the
to an Interface or Terminal Line" section on page
Catalyst 3550 Multilayer Switch Software Configuration Guide
28-16
Chapter 28
Purpose
Enter global configuration mode.
Define an extended IP access list using a name and enter
access-list configuration mode.
Note The name can be a number from 100 to 199.
In access-list configuration mode, specify the conditions allowed
or denied. Use the log keyword to get access list logging messages,
including violations.
See the "Creating a Numbered Extended ACL" section on
page 28-11 for definitions of protocols and other keywords.
• host source—A source and source wildcard of source 0.0.0.0.
host destination—A destination and destination wildcard of
•
destination 0.0.0.0.
• any—A source and source wildcard or destination and
destination wildcard of 0.0.0.0 255.255.255.255.
Note The log keyword is not supported for ACLs applied to
Layer 2 interfaces (port ACLs).
Return to privileged EXEC mode.
Show the access list configuration.
(Optional) Save your entries in the configuration file.
28-19.
Configuring Network Security with ACLs
"Applying an IP ACL
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