ALL, *

The universal wildcard. Matches all names. 

LOCAL

Matches any local host (one whose name does not contain a dot character). However, if your installation uses only canonical names, even local host names will contain dots and thus will not match this wildcard. 

UNKNOWN

Matches any user whose name is unknown, or any host whose name or address is unknown. 

Use this wildcard name carefully: 

Host names may be unavailable due to temporary DNS server problems—in which case all filters that use UNKNOWN will match all client hosts.

A network address is unavailable when the software cannot identify the type of network it is communicating with—in which case all filters that use UNKNOWN will match all client hosts on that network.

KNOWN

Matches any user whose name is known, or any host whose name and address are known.

Use this wildcard name carefully: 

Host names may be unavailable due to temporary DNS server problems—in which case all filters that use KNOWN will fail for all client hosts.

A network address is unavailable when the software cannot identify the type of network it is communicating with—in which case all filters that use KNOWN will fail for all client hosts on that network.

DNSSPOOFER

Matches any host whose DNS name does not match its own IP address.