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Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
OL-10101-02
Chapter 28 Configuring Network Security with ACLs
Configuring ACLs
Beginning in privileged EXEC mode, follow these steps to create a numbered standard IP ACL:
Use the no access-list access-list-number global configuration command to delete the entire ACL. You
cannot delete individual ACEs from numbered access lists.
Note When creating an ACL, remember that, by default, the end of the ACL contains an implicit deny
statement for all packets that it did not find a match for before reaching the end. With standard access
lists, if you omit the mask from an associated IP host address ACL specification, 0.0.0.0 is assumed to
be the mask.
This example shows how to create a standard ACL to deny access to IP host 171.69.198.102, permit
access to any others, and display the results.
Switch (config)# access-list 2 deny host 171.69.198.102
Switch (config)# access-list 2 permit any
Switch(config)# end
Switch# show access-lists
Standard IP access list 2
deny 171.69.198.102
permit any
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
access-list access-list-number {deny | permit |
remark} {source source-wildcard | host source
| any}
Define a standard IP ACL by using a source address and wildcard.
The access-list-number is a decimal number from 1 to 99 or 1300
to 1999.
Enter deny or permit to specify whether to deny or permit access
if conditions are matched.
The source is the source address of the network or host from which
the packet is being sent:
• The 32-bit quantity in dotted-decimal format.
• The keyword any as an abbreviation for source and
source-wildcard of 0.0.0.0 255.255.255.255. You do not need
to enter a source wildcard.
• The keyword host as an abbreviation for source and
source-wildcard of source 0.0.0.0.
(Optional) The source-wildcard applies wildcard bits to the
source. (See first bullet item.)
Note The log option is not supported on the switches.
Step 3
end Return to privileged EXEC mode.
Step 4
show access-lists [number | name] Show the access list configuration.
Step 5
copy running-config startup-config (Optional) Save your entries in the configuration file.