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Creating a numbered extended acl – IBM 12.1(22)EA6 User Manual

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Cisco Systems Intelligent Gigabit Ethernet Switch Modules for the IBM BladeCenter, Software Configuration Guide

24R9746

Chapter 22 Configuring Network Security with ACLs

Configuring ACLs

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

Creating a Numbered Extended ACL

Although standard ACLs use only source addresses for matching, you can use an extended ACL source
and destination addresses for matching operations and optional protocol type information for finer
granularity of control. Some protocols also have specific parameters and keywords that apply to that
protocol.

These IP protocols are supported on physical interfaces (protocol keywords are in parentheses in bold):
Internet Protocol (ip), Transmission Control Protocol (tcp), or User Datagram Protocol (udp).

Supported parameters can be grouped into these categories:

TCP

UDP

Table 22-3

lists the possible filtering parameters for ACEs for each protocol type.

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.

Command

Purpose

Table 22-3

Filtering Parameter ACEs Supported by Different IP Protocols

Filtering Parameter

1

TCP UDP

Layer 3 Parameters:

IP type of service (ToS) byte

2

Differentiated Services Code Point (DSCP)

X

X

IP source address

X

X

IP destination address

X

X

Fragments

TCP or UDP

X

X