So the port 25 on my mailserver is blocked and I'm now trying to set up my mail server with a SMTP relay to send mail with dynu.com. But i keep getting the error messages bellow when i try to send a mail from the terminal window.

In master.cf I have set the following

465 inet n - n - - smtpd

In main.cf I have set this

myhostname = rajohan.no
mydestination = localhost, rajohan.no, localhost.rajohan.no
mynetworks = [::ffff:]/104 [::1]/128

smtpd_sasl_auth_enable = yes
smtpd_sasl_password_maps = hash:/etc/postfix/sasl_password

relayhost = [relay.dynu.com]:465
smtpd_generic_maps = hash:/etc/postfix/generic

In sasl_password i have

[email protected] mypassword

In generic i have

[email protected]         [email protected]
[email protected]      [email protected]
[email protected]    [email protected]
[email protected]   [email protected]
[email protected]         [email protected]
[email protected]    [email protected]
[email protected]        [email protected]
[email protected]   [email protected]

Dec 19 22:22:49 rajohan dovecot: imap-login: Login: user=, method=PLAIN, rip=, lip=, mpid=30452, secured, session=<6DQx6LhgdJZ/AAAB>

Dec 19 22:22:49 rajohan dovecot: imap([email protected]): Logged out in=50 out=490

Dec 19 22:22:57 rajohan postfix/pickup[30405]: AEF3884669: uid=0 from=

Dec 19 22:22:57 rajohan postfix/cleanup[30461]: warning: connect to Milter service unix:/opendkim/opendkim.sock: No such file or directory

Dec 19 22:22:57 rajohan postfix/cleanup[30461]: AEF3884669: message-id=<[email protected]>

Dec 19 22:22:57 rajohan postfix/qmgr[30406]: AEF3884669: from=, size=284, nrcpt=1 (queue active)

Dec 19 22:22:57 rajohan postfix/smtp[30467]: SMTPS wrappermode (TCP port 465) requires setting "smtp_tls_wrappermode = yes", and "smtp_tls_security_level = encrypt" (or stronger)

Dec 19 22:22:59 rajohan postfix/smtp[30467]: AEF3884669: [email protected]>, relay=relay.dynu.com[]:465, delay=23, delays=21/0.08/1.3/0.33, dsn=5.0.0, status=bounced (host relay.dynu.com[] said: 530 SMTP authentication is required. (in reply to RCPT TO command))

Dec 19 22:22:59 rajohan postfix/cleanup[30461]: BFE7E84668: message-id=<[email protected]>

Dec 19 22:22:59 rajohan postfix/qmgr[30406]: BFE7E84668: from=<>, size=2190, nrcpt=1 (queue active)

Dec 19 22:22:59 rajohan postfix/trivial-rewrite[30462]: warning: do not list domain rajohan.no in BOTH mydestination and virtual_mailbox_domains

Dec 19 22:22:59 rajohan postfix/bounce[30470]: AEF3884669: sender non-delivery notification: BFE7E84668

Dec 19 22:22:59 rajohan postfix/qmgr[30406]: AEF3884669: removed

Dec 19 22:22:59 rajohan postfix/local[30471]: BFE7E84668: to=, orig_to=, relay=local, delay=0.06, delays=0.03/0/0/0.03, dsn=5.1.1, status=bounced (unknown user: "webmaster")

Dec 19 22:22:59 rajohan postfix/qmgr[30406]: BFE7E84668: removed

  • Typically you should use port 587. Port 465 may also be blocked along with port 25. If they have not yet done so, they will do it sooner or later. Dec 20, 2017 at 0:42

2 Answers 2


Your sasl_password file should be formatted like this and match that of the relayhost directive:


So, your's would look like this:

[relay.dynu.com]:465 [email protected]:mypassword

Then you need to hash the file: sudo postmap /etc/postfix/sasl_password

Now, you have a file created: /etc/postfix/sasl_password.db

Change the following directives in your main.cf (remove the d):

smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_password

Don't forget to restart postfix.

Configuring SASL authentication in the Postfix SMTP/LMTP client


It's an old thread, but my solution was to change main.cf:

smtp_tls_wrappermode = yes
smtp_tls_security_level = encrypt

And restart Postfix

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