Cisco Systems SCE 2000 4/8xFE manual Entry Formats, Order of Entries, permit any deny

Chapter 5 Connecting the Management Interfaces and Performing Initial System Configuration

Initial System Configuration

Entry Formats

Each ACL may permit/deny access to any IP address, one or more ranges of IP addresses, or one or more individual IP address. Three entry formats are available to support these options:

•Any IP address — Type the word “any”. Any IP address will be permitted or denied access.

•Range of IP addresses — Type the beginning IP address in the desired range, then enter the wildcard bits that define the range.

This wildcard functions like a reverse mask, in that all “1” bits in the wildcard indicate the corresponding bit in the IP address should be ignored. All other bits must match the corresponding bit in the specified IP address. Refer to the table below for examples.

Each range of IP addresses can be configured to be permitted or denied access.

•Individual IP address — Type the desired IP address, then enter the wildcard bits 0.0.0.0. Each individual IP address can be configured to be permitted or denied access.

Table 5-2	IP address/Wildcard bit examples
Initial IP address		Wildcard bits	Range
10.1.1.0		0.0.0.255	10.1.1.0–10.1.1.255
10.1.1.0		0.0.0.63	10.1.1.0–10.1.1.63
10.1.1.0		0.0.0.0	10.1.1.0 (individual entry)

Order of Entries

The order of the entries in the list is important. The entries in the list are tested sequentially, and the action is determined by the first entry that matches the connecting IP address. Therefore, when the entry “any” appears in an Access Control List, all succeeding entries are irrelevant.

Consider two hypothetical ACLs containing the same entries in a different order. The following list would permit access to all IP addresses, including 10.1.1.0:

permit any deny 10.1.1.0

Note that the above list could not actually be created using the setup utility, since after the “any” entry, no other entries could be added to the list.

The following list will deny access to IP address 10.1.1.0, but permit access to all others:

deny 10.1.1.0 permit any

If no entry in the assigned Access Control List matches the connection, or if the Access Control List is empty, the default action is deny.

To create the access control lists, complete the following steps:

Step 1 Enter the Access Control Lists configuration menu.

Cisco SCE 2000 4/8xFE Installation and Configuration Guide

OL-7826-05 5-13