TCP wrapper filter EXCEPT operator

The TCP wrapper access-control system supports a single operator. You can use the   operator to create exceptions to matching names or patterns when you have multiple entries in either  service-list or  client-list. For example, the expression: list1 EXCEPT list2 means that anything that matches list1 is matched, unless it also matches list2.

Here is an example: ALL: ALL EXCEPT isserver.siroe.com If this were a Deny filter, it would deny access to all services to all clients except those on the host machine isserver.siroe.com.

clauses can be nested. The expression: list1 EXCEPT list2 EXCEPT list3 is evaluated as if it were: list1 EXCEPT (list2 EXCEPT list3)

See also:
 * domainnotallowed Option
 * TCP wrapper filter syntax