Thanks to all for the input so far. I realize that a big part of my spam problem is the fact that I do not know this area very well, so have not done a whole lot to tweak the config. I really wish I had the time to study this more in depth.
Anyhow, I added "smtpd_client_restrictions" to main.cf with the RegEx suggested by Reinaldo. I have posted exerpts from master.cf and main.cf below. If anyone can see any glaring problems or stuff that I overlooked, I would much appreciate suggestions. Thanks, JB master.cf ---------------------------------------- smtp inet n - n - 100 smtpd amavisfeed unix - - n - 100 lmtp -o lmtp_data_done_timeout=1200 -o lmtp_send_xforward_command=yes -o disable_dns_lookups=yes -o max_use=20 -o message_size_limit=14000000 127.0.0.1:10025 inet n - y - 100 smtpd -o content_filter= -o smtpd_delay_reject=no -o smtpd_client_restrictions=permit_mynetworks,reject -o smtpd_helo_restrictions= -o smtpd_sender_restrictions= -o smtpd_recipient_restrictions=permit_mynetworks,reject -o smtpd_data_restrictions=reject_unauth_pipelining -o smtpd_end_of_data_restrictions= -o smtpd_restriction_classes= -o mynetworks=127.0.0.0/8 -o smtpd_error_sleep_time=0 -o smtpd_soft_error_limit=1001 -o smtpd_hard_error_limit=1000 -o smtpd_client_connection_count_limit=0 -o smtpd_client_connection_rate_limit=0 -o receive_override_options=no_header_body_checks, no_unknown_recipient_checks, no_milters -o local_header_rewrite_clients= main.cf ---------------------------------------- relay_domains = $mydestination smtpd_recipient_restrictions = permit_mynetworks permit_sasl_authenticated reject_unauth_destination smtpd_client_restrictions = reject_unauth_pipelining, permit_mynetworks, check_client_access regexp:/etc/postfix/access.regexp, reject_maps_rbl smtpd_sasl_type = dovecot smtpd_sasl_path = private/auth smtpd_sasl_auth_enable = yes broken_sasl_auth_clients = yes content_filter=amavisfeed:[127.0.0.1]:10024 access.regexp ---------------------------------- /([0-9]{1,3}(\.|-)){3}.*\.[a-z]+/ reject Generic hostname /(^a?dsl|a?dsl(\.|-)|(\.|-)a?dsl|(\.|-)d(yn|ip|ial)(\.|-)|(\.|-)cable(\.|-)|(\.|-)user(\.|-)|^dynamic|(\.|-)dynamic|dynamic(\.|-)|(\.|-)ppp(oe)?(\.|-|)|^ppp)/ reject Generic hostname