I've a postfix server running on a centOS machine. I added a secondary IP but the emails are always being sent by the 1st IP.

I have A Records:

m1.domain.com ->
m2.domain.com ->

And the reverses are: -> m1.domain.com -> m2.domain.com

If I connect with a simple PHPmailer to m1.domain.com I need to send the email from, if I connect to m2.domain.com I need to send the email from

I tried to use the sender_dependent_default_transport_maps defining 2 different smtp_bind_address on master.cf but it does nothing... maybe because I'm using this configuration with postfix + dovecot + mysql.


Thank you in advance.

  • did you add another MX record to your DNS? – sysfiend Jan 13 '17 at 17:57
  • I have no MX records created yet, which ones should I put? I don't think it's because of it. – John V Jan 13 '17 at 18:00
  • you need to add both your mail servers. Here, read: support.simpledns.com/kb/a44/… – sysfiend Jan 13 '17 at 18:05
  • The problem is sending, not receiving. – John V Jan 13 '17 at 18:08
  • I would say that, if everything is properly configured (can't know untill you post relevant configurations), it's an issue with DNS requests. – sysfiend Jan 13 '17 at 18:12

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