I have someone telling me that they can't send email to my mail server. I checked the logs and it appears that Postfix is not happy with the way their client or server is sending the message to me. I want to understand what is causing this. I would like to know if anyone can please help me understand what is at fault here. I am guessing that this is being caused by:
smtpd_sender_restrictions = reject_unknown_reverse_client_hostname Can someone please help me understand? Should I have the noted above restriction in my main.cf or is this being too restrictive? Is that even the correct parameter that is causing the delivery failure? I removed the senders user name and my recipients full email address for privacy. Sep 22 18:11:55 mail postfix/smtpd[6052]: NOQUEUE: reject: RCPT from unknown[204.117.196.2]: 450 4.7.1 Client host rejected: cannot find your reverse hostname, [204.117.196.2]; from=<*******...@pmcatt-ppss.com> to=<**********...@***.com> proto=ESMTP helo=<mail.pmcatt-ppss.com> **Postconf -n* alias_database = hash:/etc/aliases alias_maps = hash:/etc/aliases broken_sasl_auth_clients = yes command_directory = /usr/sbin config_directory = /etc/postfix content_filter = amavisfeed:[127.0.0.1]:10024 daemon_directory = /usr/libexec/postfix home_mailbox = Maildir/ html_directory = no inet_interfaces = all mail_owner = postfix mailq_path = /usr/bin/mailq.postfix manpage_directory = /usr/share/man mydestination = $myhostname, $mydomain, mail.$mydomain mydomain = iamghost.com myhostname = mail.iamghost.com mynetworks = $config_directory/mynetworks myorigin = $mydomain newaliases_path = /usr/bin/newaliases.postfix queue_directory = /var/spool/postfix readme_directory = /usr/share/doc/postfix-2.3.3/README_FILES recipient_delimiter = + relay_domains = sample_directory = /usr/share/doc/postfix-2.3.3/samples sendmail_path = /usr/sbin/sendmail.postfix setgid_group = postdrop smtpd_banner = $myhostname ESMTP smtpd_delay_reject = yes smtpd_helo_required = yes smtpd_helo_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_non_fqdn_helo_hostname, reject_invalid_helo_hostname, permit smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_pipelining, reject_non_fqdn_recipient, reject_unknown_recipient_domain, reject_unauth_destination, reject_unlisted_recipient, check_policy_service unix:postgrey/socket, check_sender_access hash:/etc/postfix/sender_access, reject_rbl_client zen.spamhaus.org, reject_rbl_client bl.spamcop.net, permit smtpd_sasl_auth_enable = yes smtpd_sasl_path = private/auth smtpd_sasl_security_options = noanonymous smtpd_sasl_type = dovecot smtpd_sender_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_non_fqdn_sender, reject_unknown_sender_domain, reject_unknown_reverse_client_hostname, permit smtpd_tls_CAfile = /etc/ssl/intermediate.crt smtpd_tls_auth_only = yes smtpd_tls_cert_file = /etc/ssl/mail.crt smtpd_tls_key_file = /etc/ssl/mail.key smtpd_tls_loglevel = 1 smtpd_tls_security_level = may smtpd_tls_session_cache_database = btree:/var/spool/postfix/smtpd_tls_cache smtpd_tls_session_cache_timeout = 3600s tls_random_source = dev:/dev/urandom unknown_local_recipient_reject_code = 550
