I'm trying to setup postfix as MTA on a AWS EC2 instance. I want to use this as mailserver for my domains and want to use it along with Outlook/Thunderbird.

I've never setup postfix before, therefore I used this great guide here:


Now I can connect to the server via STARTTLS to mail.mydomain.com and send emails to my own email account admin@mydomain.com via Thunderbird.

However when I try to send an email to an external domain myemail@gmail.com I get an error Relay access denied.

The logs show:

May 31 14:55:58 ip-172-31-23-97 postfix/smtpd[13500]: NOQUEUE: reject: RCPT from myhostname[]: 554 5.7.1 <myemail@gmail.com>: Relay access denied; from=<admin@mydomain.com> to=<myemail@gmail.com> proto=ESMTP helo=<[]>

My postfix config:


I know there are many pages out there that address this issue.

Mainly the issue can be fixed by adjusting mynetworks, smtpd_recipient_restrictions or smtpd_relay_restrictions but none of the changes fixed my issue.

What can I do to resolve this?


I think the problem is here

#mynetworks =,

Try to add and network and del #

mynetworks =,
  • Unfortunately after uncommenting the line and adding your suggestion I'm still getting the error – maddo7 May 31 '16 at 17:37
  • Is this your LAN – stambata May 31 '16 at 17:45
  • Edit: Yes, that's the LAN IP of my windows PC from where I try to connect. How can the LAN IP be related to this? – maddo7 May 31 '16 at 18:25
  • When I insert the internet IP address of my connection to that value, it sends the email without problems: mynetworks =,,,, xxx.193.4.67 but I don't want to manually insert the IP addresses of all clients I want to use to connect. – maddo7 May 31 '16 at 18:29
  • This is another issue :). and your solution is SASL postfix.org/SASL_README.html – stambata May 31 '16 at 20:08

smtpd_sasl_auth_enable = yes is required. (not smtp_sasl_auth_enable)

Perhaps, it may be necessary to change the order of smtpd_recipient_restrictions.

smtpd_recipient_restrictions = permit_mynetworks, permit_sasl_authenticated, (other reject rules)

  • Are you sure? I don't have sasl installed on the machine and smtp_sasl_auth_enable is only used for the smtp connection for amazon's ses smtp server. – maddo7 May 31 '16 at 16:05

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