Chapter 23
Configuring Network Security with ACLs
Beginning in privileged EXEC mode, follow these steps to create an extended ACL:
Command
Step 1
configure terminal
Step 2
access-list access-list-number
{deny | permit | remark} protocol
{source source-wildcard | host
source | any } [operator port]
{destination destination-wildcard |
host destination | any} [operator
port]
Step 3
show access-lists [number | name]
Step 4
copy running-config
startup-config
78-11380-04
Purpose
Enter global configuration mode.
Define an extended IP access list and the access conditions.
The access-list-number is a decimal number from 100 to 199 or 2000 to 2699.
Enter deny or permit to specify whether to deny or permit the packet if
conditions are matched.
For protocol, enter the name or number of an IP protocol: ip, tcp, or udp. To
match any Internet protocol (including TCP and UDP), use the keyword ip.
Note
This step includes options for most IP protocols.
The source is the number of the network or host from which the packet is sent.
The source-wildcard applies wildcard bits to the source.
The destination is the network or host number to which the packet is sent.
Define a destination or source port.
•
The operator can be only eq (equal).
•
If operator is after source source-wildcard, conditions match when the
source port matches the defined port.
•
If operator is after destination destination-wildcard, conditions match
when the destination port matches the defined port.
The port is a decimal number or name of a TCP or UDP port. The number
•
can be from 0 to 65535.
Use TCP port names only for TCP traffic.
•
Use UDP port names only for UDP traffic.
•
The destination-wildcard applies wildcard bits to the destination.
Source, source-wildcard, destination, and destination-wildcard can be
specified in three ways:
•
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 or any source host.
The keyword host, followed by the 32-bit quantity in dotted-decimal
•
format, as an abbreviation for a single host with source and
source-wildcard of source 0.0.0.0.
Only the ip, tcp, and udp protocols are supported on Catalyst 2950
Note
switches.
Verify the access list configuration.
(Optional) Save your entries in the configuration file.
Catalyst 2950 Desktop Switch Software Configuration Guide
Configuring ACLs
23-11