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Nov 22 11:57:32 blah postfix/smtpd[10485]: NOQUEUE: reject: RCPT from mail-ua0-f171.google.com[209.85.xxx.xxx]: 454 4.7.1 <[email protected]>: Relay access denied; from=<[email protected]> to=<[email protected] ...
O que isso está lhe dizendo é que sua máquina está se recusando a retransmitir uma mensagem do Google para [email protected]. Agora, você sabe que sua máquina é example.com, mas claramente sua máquina não.
Solução: modifique a configuração local para incluir example.com como um nome para sua máquina local. Existe um documento de fácil leitura disponível no site do Postfix (((BASIC_CONFIGURATION_README.html) [ link ) que explica como configurá-lo:
My own domain name
The mydomain parameter specifies the parent domain of $myhostname. By default, it is derived from $myhostname by stripping off the first part (unless the result would be a top-level domain).
Conversely, if you specify mydomain in main.cf, then Postfix will use its value to generate a fully-qualified default value for the myhostname parameter.
Examples (specify only one of the following):
/etc/postfix/main.cf: mydomain = local.domain mydomain = virtual.domain (virtual interface)
What domains to receive mail for
The mydestination parameter specifies what domains this machine will deliver locally, instead of forwarding to another machine. The default is to receive mail for the machine itself. See the VIRTUAL_README file for how to configure Postfix for hosted domains.
You can specify zero or more domain names, "/file/name" patterns and/or "type:table" lookup tables (such as hash:, btree:, nis:, ldap:, or mysql:), separated by whitespace and/or commas. A "/file/name" pattern is replaced by its contents; "type:table" requests that a table lookup is done and merely tests for existence: the lookup result is ignored.
IMPORTANT: If your machine is a mail server for its entire domain, you must list $mydomain as well.
Example 1: default setting.
/etc/postfix/main.cf: mydestination = $myhostname localhost.$mydomain localhost
Example 2: domain-wide mail server.
/etc/postfix/main.cf: mydestination = $myhostname localhost.$mydomain localhost $mydomain
Example 3: host with multiple DNS A records.
/etc/postfix/main.cf: mydestination = $myhostname localhost.$mydomain localhost www.$mydomain ftp.$mydomain
Caution: in order to avoid mail delivery loops, you must list all hostnames of the machine, including $myhostname, and localhost.$mydomain.
Então, isso deve ser suficiente:
mydomain = example.com
...
mydestination = $myhostname localhost.$mydomain localhost $mydomain