I'll continue here since Krosrow's issue has been resolved (so I'm not really hijacking the thread).
I now have the following defined in mailbox_transport_maps: [EMAIL PROTECTED] smtp:mx.myexternaldomain.com Yet when I attempt to send mail to the local system at [EMAIL PROTECTED] I get 554 5.7.1 <[EMAIL PROTECTED]>: Relay access denied quit 221 2.0.0 Bye Why? Shouldn't the smtp transport map deliver the message to the defined external MX even when the user/domain [EMAIL PROTECTED] is not locally defined since the configuration page says about mailbox_transport_maps: `Optional lookup tables with per-recipient message delivery transports to use for local(8) mailbox delivery, whether or not the recipients are found in the UNIX passwd database.', and since there is nothing higher in precedence (above mailbox_transport_maps) of local overriding the mail delivery instructions? The user/domain "[EMAIL PROTECTED]" is currently not defined anywhere else on the local system except in mailbox_transport_maps. My main.cf: ## DELTAS TO MAIN.CF.DEFAULT ## ## For the syntax, and for a complete parameter list, ## see the postconf(5) manual page ("man 5 postconf"), ## or see http://www.postfix.org/postconf.5.html #soft_bounce = no debug_peer_level = 9 debug_peer_list = 127.0.0.1 data_directory = /var/db/postfix queue_directory = /var/spool/postfix command_directory = /usr/local/sbin daemon_directory = /usr/local/libexec/postfix manpage_directory = /usr/local/man sendmail_path = /usr/local/sbin/sendmail newaliases_path = /usr/local/bin/newaliases mailq_path = /usr/local/bin/mailq readme_directory = $config_directory/README_FILES sample_directory = /usr/local/etc/postfix html_directory = no mail_owner = postfix setgid_group = maildrop myhostname = my.localdomain.com mydomain = my.localdomain.com myorigin = $myhostname mydestination = $myhostname localhost.$mydomain localhost mynetworks_style = host mynetworks = 192.168.1.0/24 relay_domains = $mydestination #delay_warning_time = 4h # define here the listening interfaces # that do _not_ have custom rules inet_interfaces = 127.0.0.1, 192.168.1.99 # execute `postsuper -r ALL' & reload if you disable content_filter! content_filter = scan:[127.0.0.1]:10025 receive_override_options = no_address_mappings smtpd_helo_required = yes smtpd_sasl_auth_enable = yes smtpd_sasl_type = dovecot smtpd_sasl_path = private/auth-client broken_sasl_auth_clients = yes disable_vrfy_command = yes dovecot_destination_recipient_limit = 1 mailbox_transport_maps = hash:$config_directory/tables/mailbox_transport_maps mailbox_transport = dovecot mailbox_command = /usr/local/libexec/dovecot/deliver virtual_transport = dovecot virtual_mailbox_base = /home/vmail virtual_mailbox_domains = $config_directory/tables/virtual_mailbox_domains virtual_mailbox_maps = hash:$config_directory/tables/virtual_mailbox_maps virtual_alias_domains = $config_directory/tables/virtual_alias_domains virtual_alias_maps = hash:$config_directory/tables/virtual_alias_maps pcre:$config_directory/tables/virtual_alias_maps_pcre virtual_uid_maps = static:2000 virtual_gid_maps = static:2000 smtpd_client_restrictions = permit_mynetworks permit_inet_interfaces reject smtpd_client_restrictions_katharion = permit_mynetworks permit_sasl_authenticated check_client_access hash:$config_directory/tables/smtpd_client_access_katharion reject smtpd_helo_restrictions = reject_invalid_helo_hostname reject_non_fqdn_helo_hostname permit_mynetworks permit_sasl_authenticated reject_unknown_helo_hostname smtpd_etrn_restrictions = permit_mynetworks reject smtpd_recipient_restrictions = reject_non_fqdn_recipient reject_non_fqdn_sender reject_unknown_sender_domain reject_unknown_recipient_domain reject_unverified_recipient check_recipient_access pcre:$config_directory/tables/smtpd_recipient_access # permit_mynetworks #disabled for testing purposes permit_sasl_authenticated reject_non_fqdn_hostname reject_invalid_hostname reject_unauth_destination smtpd_recipient_restrictions_katharion = reject_non_fqdn_recipient reject_non_fqdn_sender reject_unknown_sender_domain reject_unknown_recipient_domain reject_unverified_recipient check_recipient_access pcre:$config_directory/tables/smtpd_recipient_access_katharion permit_mynetworks permit_sasl_authenticated reject_non_fqdn_hostname reject_invalid_hostname reject_unauth_destination smtpd_data_restrictions = reject_multi_recipient_bounce reject_unauth_pipelining -- smtpd_recipient_tables (the interface I'm trying to send through) includes # reject domains that are served by Katharion # on the generic smtpd interface /(@virtualdomain1\.com| @virtualdomain2\.com| @virtualdomain3\.com| @virtualdomain4\.com| @virtualdomain5\.com)$/ REJECT -- Many thanks for any insights! Ville