Hi all I'm having a problem with a mail destination domain name getting changed while in transit between sender server and my receiving server. I think the problem may lie in the DNS, but I'm not 100% sure and would appreciate some input from more experienced admins. I have a basic setup which is mail destination for itself and also hosting virtual domains. My DNS config for the base host is: Code: host.my.dom. A 1.2.3.4 host.my dom. MX 20 host.my.dom. 4.3.2.1.in-addr.arpa. PTR host.my.dom. DNS config for the virtual domains are: Code: my.dom MX 10 host.my.dom. # virtual email - catch and deliver [email protected] addresses email.my.dom CNAME host.my.dom. # for convenient access to webmail software another.my.dom CNAME host.my.dom. # for convenient access to web pages of "virtual host" another.my.dom MX 10 host.my.dom. # virtual email - catch and delivery [email protected] addresses The problem lies in emails that are addressed to [email protected] Sometimes they are handed over to postfix exactly as they should be. i.e. as [email protected]. When this happens all is smooth, because that domain is handled virtually. But sometimes they get handed over to postfix as user@[B]host[/B].my.dom and then delivery fails because host.my.dom is not virtual and therefore user must exist in /etc/aliases, which it doesn't. At first I thought I had my virtual setups wrong and have done a fair bit of research on virtual domains and postfix and eventually resorted to turning on debugging in postfix. Through that I have determined that the problem starts when the relaying mail server issues the RCPT TO command to postfix. Already at that stage the email domain name has been changed, so instead of: Code: RCPT TO:<[email protected]> I see: Code: RCPT TO:<[email protected]> And yes, I'm sure I'm typing the recipient address properly. The only scenario that I can think of is that the relaying domain (I'm sending from a webmail client on another system) is doing some wacky antispam check. Something like: Code: RECEIVED ADDRESS: <[email protected]> GET IP: another.my.dom -> 1.2.3.4 RDNS CHECK: 4.3.2.1.in-addr.arpa. -> host.my.dom RELAYED ADDRESS: <[email protected]> Is something like that feasible? possible? allowed? a bug? Appreciate any insights. Thanks
Code: user@host:~$ cat /etc/postfix/main.cf | grep -v ^# smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu) biff = no append_dot_mydomain = no readme_directory = /usr/share/doc/postfix smtpd_tls_cert_file = /etc/postfix/smtpd.cert smtpd_tls_key_file = /etc/postfix/smtpd.key smtpd_use_tls = yes smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache myhostname = host.my.dom alias_maps = hash:/etc/aliases alias_database = hash:/etc/aliases myorigin = /etc/mailname mydestination = $myhostname, localhost.$mydomain, localhost, localhost.localdomain relayhost = mynetworks = 127.0.0.0/8 mailbox_size_limit = 0 recipient_delimiter = + inet_interfaces = all html_directory = /usr/share/doc/postfix/html virtual_alias_domains = virtual_alias_maps = proxy:mysql:/etc/postfix/mysql-virtual_forwardings.cf, mysql:/etc/postfix/mysql-virtual_email2email.cf virtual_mailbox_domains = proxy:mysql:/etc/postfix/mysql-virtual_domains.cf virtual_mailbox_maps = proxy:mysql:/etc/postfix/mysql-virtual_mailboxes.cf virtual_mailbox_base = /home/vmail virtual_uid_maps = static:5000 virtual_gid_maps = static:5000 smtpd_sasl_auth_enable = yes broken_sasl_auth_clients = yes smtpd_sasl_authenticated_header = yes smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination, check_policy_service inet:127.0.0.1:60000 transport_maps = proxy:mysql:/etc/postfix/mysql-virtual_transports.cf virtual_create_maildirsize = yes virtual_maildir_extended = yes virtual_mailbox_limit_maps = proxy:mysql:/etc/postfix/mysql-virtual_mailbox_limit_maps.cf virtual_mailbox_limit_override = yes virtual_maildir_limit_message = "The user you are trying to reach is over quota." virtual_overquota_bounce = yes 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 $virtual_mailbox_limit_maps content_filter = amavis:[127.0.0.1]:10024 receive_override_options = no_address_mappings mailman_destination_recipient_limit = 1 Nothing too out of the ordinary there. It should look quite familiar. I'm pretty sure that my postfix is not the culprit because the change is taking place even before the email arrives at my system. I've tried from various webmail clients (gmail, hotmail etc.) and so far, the problem only happens with one of them. I have opened a support ticket with the system concerned, but only got what looks like a junior level response so far.
