Postfix won't connect to relay SMTP server

Dimitrios Dalagiorgos

6/16/23, 7:49 AM

We have a Debian virtual machine and I want to use postfix and mailutils to send email via a relay SMTP server

Trying to connect to the SMTP server with telnet works.

telnet mail.sch.gr 587
Trying 194.63.239.110...
Connected to mail.sch.gr.
Escape character is '^]'.
220 mail26.sch.gr ESMTP Postfix (Debian/GNU)
AUTH LOGIN
334 VXNlcm5hbWU6
*************
334 UGFzc3dvcmQ6
*************
235 2.7.0 Authentication successful

However, if I try to send an email, the email isn't sent, the mail.log says

(SASL authentication failed; server mail.sch.gr[194.63.239.110] said: 535 5.7.8 Error: authentication failed: UGFzc3dvcmQ6)

my main.cf is this:

# See /usr/share/postfix/main.cf.dist for a commented, more complete version


# Debian specific:  Specifying a file name will cause the first
# line of that file to be used as the name.  The Debian default
# is /etc/mailname.
#myorigin = /etc/mailname

smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
biff = no

# appending .domain is the MUA's job.
append_dot_mydomain = no

# Uncomment the next line to generate "delayed mail" warnings
#delay_warning_time = 4h

readme_directory = no

# See http://www.postfix.org/COMPATIBILITY_README.html -- default to 2 on
# fresh installs.
compatibility_level = 2

relayhost=[mail.sch.gr]:587
smtp_sasl_mechanism_filter = login
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/sasl_passwd
smtp_sasl_security_options = noanonymous
smtp_tls_CAfile = /etc/postfix/cacert.pem
smtp_use_tls=yes

inet_protocols = ipv4

the sasl_passwd is like this:

[mail.sch.gr]:587 [email protected]:password

(obviously user and password are replaced with the actual username and password)

I don't know how to proceed...

0 + 0

debian

smtp

postfix

Gerrit

6/16/23, 8:03 AM

Any warnings in the /var/log/mail.log? Did you use postmap hash:/etc/postfix/sasl_passwd. Also try mail.sch.gr without the brackets in the sasl_passwd file.

Lacek

6/16/23, 8:40 AM

Did you create a db file from the `sasl_passwd` with the `postmap hash:sasl_passwd` command?

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Postfix won't connect to relay SMTP server

TH: Postfix จะไม่เชื่อมต่อกับเซิร์ฟเวอร์ส่งต่อ SMTP

RO: Postfix nu se va conecta la serverul SMTP releu

RU: Postfix не будет подключаться к серверу ретрансляции SMTP

VI: Postfix sẽ không kết nối với máy chủ SMTP chuyển tiếp

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