Questions tagged [smtp]
SMTP is a protocol built upon TCP/IP, used for outgoing email transmissions, and email relaying. It uses ports 25 (clear) and 465 (SSL) by default.
315 questions
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35 views
Adding an account of postfixmailserver failed on Outlook
I need to add a new account to Outlook. This account belongs to a postfixmailserver. For POP settings, I set port number 110 for incoming and port number 25 for outgoing mail. As the server doesn't ...
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0 votes
1 answer
52 views
Testing postfix mail server with POP3 fails
PostfixAdmin installed successfully. To test whether internal sending and receiving mail work, I used SMTP to send mail: telnet mail.example.com 25 Trying 94.284.174.110... Connected to mail.example....
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0 votes
1 answer
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Why SMTP command is running always?
Almost always I can see many smtp processes in ps aux command output like this: postfix 924674 0.4 0.0 44460 9212 ? S 18:54 0:00 smtp -t unix -u -c postfix 924675 0.2 0.0 44460 ...
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126 views
Sendmail wont work for my ubuntu terminal server (Ubuntu 24.04.2)
I'm currently attempting (and failing) to set up an SMTP mail server on my Ubuntu server so I can recieve emails from the contact page of my php based website. I was planning to send these emails ...
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229 views
Receiving email with OpenSMTPD fails with 550 Invalid recipient
I am trying to set up a mailserver using OpenSMTPD. My configuration is: listen on enp4s0f2 action "save" maildir "/mail/%{rcpt}" match for rcpt-to regex ".*" action &...
1 vote
0 answers
78 views
Lua SMTP Script with STARTTLS Fails to Authenticate
🔍 Context I'm working on a Lua script that sends emails via SMTP with STARTTLS. The script successfully connects to the SMTP server, but authentication sometimes fails with the error: authentication ...
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1 vote
0 answers
203 views
Thunderbird 115.13.0 cannot connect authenticated user via OAuth2 to Microsoft Outlook365
I've Thunderbird 115.13.0 on Ubuntu 22.04 and I have my email which is configured properly automatically by Thunderbird for IMAP and SMTP servers from Microsoft outlook office 365. However, now it has ...
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Routing external network traffic to a service that only listens on loopback
I'm running protonmail-bridge on a server on my home network, and I'd like to have several other machines utilize it as their IMAP/SMTP server without having to run duplicate copies of the bridge ...
1 vote
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288 views
How to forward one email to two SMTP server using postfix?
My Requirements I have two email servers, james and winmail. They hold same users, for example, account [email protected] exists both in james and winmail. When someone sends a email to [email protected], I ...
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0 votes
1 answer
390 views
Postfix TLS Anonymous and Untrusted
We use Postfix on a RHEL server to distribute email to our opted-in users each morning. We recently enabled smtp (outbound) TLS. The majority of our email is delivered on Trusted TLS Connections. ...
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0 votes
2 answers
401 views
emails rejected from various Linux based systems due to perceived header syntax failure when using distribution lists
What am I missing... Given: Linux-stack based email server system (hosted) with webmail component. Various email clients and other webmail systems involved and tested with this. We are distributing ...
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1 vote
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567 views
How to set HELO/EHLO on Exim accordingly to match sending domain
I have a VPS server, which is used to send emails. On that server I have 2 domain names attached and correctly configured with 2 different IP's. DNS is set as well to match sending IP's accordingly: ...
0 votes
1 answer
99 views
Split messages from one inbox to another 2 inboxes based on content
is there a way via Postfix and or procmail for example or another software to forward e-mails from one inbox to another 2 inboxes where each message goes either to one inbox or the other based on ...
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1 vote
1 answer
2k views
How do I resolve a TLS Error associated with smtpd?
I found the following in the logs: sssd_kcm[425899]: Starting up postfix/submission/smtpd[425910]: initializing the server-side TLS engine postfix/submission/smtpd[425910]: connect from unknown[::1] ...
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6 votes
2 answers
2k views
Light program (mini MTA?) for system mail (only sending/relay via external server with unattended-upgrades, cron, smartmontools, etc.)
I've come across different names in different places: Light MTA, Remote MTA, Smarthost, etc. Generally, I do not want to install a full-fledged mail server (such as sendmail, postfix, exim), but only ...
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