Working with decimal representations of binary wildcard
mask bits can be tedious. For the most common uses of wildcard masking, you can use
abbreviations. These abbreviations reduce how many numbers you are required to enter while
con?¬?guring address test conditions. Figure 6-11 shows the wildcard masks used to match a
speci?¬?c host or to match all (any) host.
Figure 6-11 Special Case Wildcard Masks
Instead of entering 172.30.16.29 0.0.0.0, you can use the string host 172.30.16.29. Using the
abbreviation host communicates the same test condition to the Cisco IOS ACL Software.
Instead of entering 0.0.0.0 255.255.255.255, you can use the word any by itself as the keyword.
Using the abbreviation any communicates the same test condition to the Cisco IOS ACL Software.
Summary of ACL Operations
The following summarizes the key points that were discussed in this section:
?– ACLs can be used for IP packet ?¬?ltering or to identify traf?¬?c to assign it special handling.
?– ACLs perform top-down processing and can be con?¬?gured for incoming or outgoing traf?¬?c.
?– You can create an ACL using a named or numbered ACL. Named or numbered ACLs can be
con?¬?gured as standard or extended ACLs, which determines what they can ?¬?lter.
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