+TK/01 Added an 'spf' lookup type that will return an SPF result for a given
+ email address (the key) and an IP address (the database):
+
+ ${lookup {tom@duncanthrax.net} spf{217.115.139.137}}
+
+ The lookup will return the same result strings as they can appear in
+ $spf_result (pass,fail,softfail,neutral,none,err_perm,err_temp). The
+ lookup is armored in EXPERIMENTAL_SPF. Currently, only IPv4 addresses
+ are supported.
+
+ Patch submitted by Chris Webb <chris@arachsys.com>.
+