I think the link i gave in above post should be clear enough:
##
# Whitelist
#############
IP Whitelisting format:
INSERT INTO whitelist (_whitelist,_description) \
VALUES ('127.%.%.%','# localhost');
INSERT INTO whitelist (_whitelist,_description) \
VALUES ('192.168.2.10','# lan server');
Sender Whitelisting format:
INSERT INTO whitelist_sender (_whitelist,_description) \
VALUES ('camis@mweb.co.za','# whitelist single address');
INSERT INTO whitelist_sender (_whitelist,_description) \
VALUES ('@mweb.co.za','# whitelist entire domain');
Please note that address whitelist will be matched only against
the sender address. For recipient whitelisting, please refer
to the opt-in/opt-out section below.
DNS name whitelisting
INSERT INTO whitelist_dnsname (_whitelist,_description) \
VALUES ('%.mweb.co.za','# whitelist *.mweb.co.za');
INSERT INTO whitelist_dnsname (_whitelist,_description) \
VALUES ('%.mail.mud.yahoo.com','# whitelist all yahoo mud mailservers');
INSERT INTO whitelist_dnsname (_whitelist,_description) \
VALUES ('n10.bulk.dcn.yahoo.com','# whitelist only this mailserver');
DNS name whitelisting works as follows:
[logwall01][/]# host web32804.mail.mud.yahoo.com
web32804.mail.mud.yahoo.com has address 68.142.206.34
[logwall01][/]# host 68.142.206.34
34.206.142.68.in-addr.arpa domain name pointer web32804.mail.mud.yahoo.com.
The forward and reverse DNS *must* match otherwise it will not work.
If forward and reverse dns match, then the whitelisting can work.