I have started receiving the transcript below from one of our email servers.
The pattern is consistent with one email queued and being retried from serv1.copahost.com, i.e. it repeats from same host, but less and less frequently as if backing off. I've tried to contact the remote admin to see if there is anything unusual about the message/server without success. During this period I receive emails routinely to the address shown (domain-ad...@zynet.net) without issue, I see no similar errors about server configuration in the log other than from this one host. Anyone seen anything similar not caused by a configuration error? It looks a lot like some sort of data related problem, but cutting and pasting the transcript works as expect, so seems unlikely the essence of it is captured in the transcript. The lookup of recipient is done in Postgres database query, so plenty of scope for mistakes by myself or the server being busy, but previously Postfix has always done the right thing, or given an obvious error message when there is a database issue. Host has Debian Lenny ii postfix 2.5.5-1.1 ii postfix-doc 2.5.5-1.1 ii postfix-pgsql 2.5.5-1.1 Transcript of session follows. Out: 220 h7.zynet2.co.uk ESMTP Postfix (Debian/GNU) In: EHLO serv1.copahost.com Out: 250-h7.zynet2.co.uk Out: 250-PIPELINING Out: 250-SIZE 20000000 Out: 250-ETRN Out: 250-ENHANCEDSTATUSCODES Out: 250-8BITMIME Out: 250 DSN In: MAIL FROM:<nob...@serv1.copahost.com> SIZE=1770 Out: 250 2.1.0 Ok In: RCPT TO:<domain-ad...@zynet.net> Out: 451 4.3.5 Server configuration error In: DATA Out: 554 5.5.1 Error: no valid recipients In: QUIT Out: 221 2.0.0 Bye # postconf -n alias_database = hash:/etc/aliases alias_maps = hash:/etc/aliases append_dot_mydomain = no biff = no config_directory = /etc/postfix default_process_limit = 200 disable_vrfy_command = yes header_checks = regexp:/etc/postfix/header_checks home_mailbox = Maildir/ html_directory = /usr/share/doc/postfix/html inet_interfaces = all inet_protocols = ipv4 mailbox_size_limit = 51200000 message_size_limit = 20000000 mydestination = localhost.localdomain localhost.localdomain localhost h7.zynet2.co.uk myhostname = h7.zynet2.co.uk mynetworks = 127.0.0.0/8, 212.24.80.0/27, 212.24.80.32/27, 212.24.80.64/27 myorigin = /etc/mailname proxy_read_maps = $local_recipient_maps $mydestination $virtual_alias_maps $virtual_alias_domains $virtual_mailbox_maps $virtual_mailbox_domains $relay_recipient_maps $relay_domains $canonical_maps $sender_canonical_maps $recipient_canonical_maps $relocated_maps $transport_maps $mynetworks proxy:pgsql:/etc/postfix/pgsql-valid-rcpt.cf readme_directory = /usr/share/doc/postfix recipient_delimiter = - relayhost = smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU) smtpd_client_restrictions = cidr:/etc/postfix/cidr-badips smtpd_delay_reject = yes smtpd_hard_error_limit = 10 smtpd_helo_required = yes smtpd_helo_restrictions = permit_mynetworks, check_helo_access hash:/etc/postfix/helo_access, permit smtpd_junk_command_limit = 10 smtpd_recipient_restrictions = permit_mynetworks, reject_rbl_client zen.spamhaus.org, check_policy_service inet:127.0.0.1:60000, check_recipient_access hash:/etc/postfix/verify_recipient, check_recipient_access hash:/etc/postfix/relay-domains, check_recipient_access proxy:pgsql:/etc/postfix/pgsql-valid-rcpt.cf, reject_unauth_destination smtpd_sender_restrictions = hash:/etc/postfix/access, reject_unknown_sender_domain transport_maps = hash:/etc/postfix/transport unknown_address_reject_code = 554 unverified_recipient_reject_code = 550 virtual_alias_domains = proxy:pgsql:/etc/postfix/pgsql-email-virt-domains.cf virtual_alias_maps = proxy:pgsql:/etc/postfix/pgsql-email-virtual.cf virtual_gid_maps = static:5000 virtual_mailbox_base = /var/spool/mail virtual_mailbox_domains = pop.mail.zynet.net virtual_mailbox_maps = hash:/etc/postfix/vmailbox virtual_minimum_uid = 100 virtual_uid_maps = static:5000
