1.5 Access List Overview
1.5.7 How to use the wildcard any
Working with decimal representations of binary wildcard mask bits can be tedious.  For the most common uses of wildcard masking, you can use abbreviation words. These abbreviation words reduce how many numbers an administrator will be required to enter while configuring address test conditions. One example where you can use an abbreviation instead of a long wildcard mask string is when you want to match any address.

Consider a network administrator who wants to specify that any destination address will be permitted in an access list test. To indicate any IP address, the administrator would enter 0.0.0.0; then to indicate that the access list should ignore (allow without checking) any value, the corresponding wildcard mask bits for this address would be all ones (that is, 255.255.255.255).

The administrator can use the abbreviation any to communicate this same test condition to Cisco IOS access list software. Instead of typing 0.0.0.0 255.255.255.255, the administrator can use the word any by itself as the keyword.