Questions tagged [postfix]

Free and open source mail transfer agent (MTA) that routes and delivers email. When asking about postfix problem, please include the relevant maillog lines and output of the following command: `postconf -n` (non-default content of main.cf) and `postconf -M` (content of master.cf)

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15 votes
7 answers
34k views

How to remove Postfix queue messages sent to a specific domain

I have a server with multiple domains. How can I clear all Postfix queue messages for a specific domain?
0 votes
3 answers
205 views

Postfix sending duplicate emails under different userid's, how to fix?

I can't find a reason for it in the postfix settings, but duplicate emails are being sent, under different uid's. Looking at the email headers, they have unique ids, and each with a different Postfix, ...
10 votes
2 answers
15k views

Restricting outgoing mail to specific domains in From Address using Postfix

For reasons that make me want to hurt myself, an application I am required to support has the ability to send mail using a 'MAIL FROM' address of any domain. Because I am unable to lock down the ...
1 vote
1 answer
53 views

Postfix - can't limit active queue

One of the destinations I send email to has unusual performance characteristics. The active queue can fill up with messages for this domain, blocking sending to other domains. I want to limit the ...
0 votes
1 answer
104 views

Email from any outside domain bounces back with 554 5.7.1 Relay access denied error

i have setup postfix 3.6 on my ubuntu 22.04 vps (cyberpanel) with dovecot and roundcube as my webmail. i managed to fix outgoing emails but now, i am getting relay access denied errors. this is my ...
2 votes
1 answer
37 views

SASL authentication failure: Password verification failed even when it works with testsaslauthd

I'm having some trouble configuring client authentication using saslauthd and postfix on ubuntu 22.04. The issue is that users are not getting authenticated although the user exists. It's my first ...
-1 votes
1 answer
3k views

Email not Reaching iCloud Mail Servers

I recently created a new VPS and installed an email server using Modoboa. Everything seemed to be working and fine until I sent an email to an @icloud.com address. The iCloud user never got my email, ...
0 votes
3 answers
61 views

Why is Postfix sending private information? [duplicate]

My (external) webserver has postfix installed. I use it as a SMTP server for my private email. I'm currently investigating a problem where hotmail/outlook/live sees incoming email from me as spam, ...
1 vote
2 answers
7k views

Postfix " Sender address rejected: not owned by user"

I've setup a Postfix/Dovecot mail server on AWS. I've implemented self-signed TLS authorization, connected to it from and external TBird client and tried to send/receive email. TBird is able to ...
0 votes
1 answer
345 views

Postfix starts before /etc/resolv.conf is ready and fails to resolve DNS

I have configured Postfix to send all emails to a smart host, and it can work for weeks without problems. But every now and then it stops working and shows messages such as these in the log (the first ...
0 votes
1 answer
31 views

Can authentication with a relay be disabled for a specific address in smtp_sasl_password_maps?

Some email hosters are jerks. No matter your blacklist standing, SPK, DKIM, or DMARC, they will block your emails. To deal with that, I've set up a relay using sender_dependent_relayhost_maps. There ...
-3 votes
0 answers
31 views

Add custom header to email

I have a question here that I'm a bit lost on, I need to create an email server with postfix, sendmail or something like that, but with something very specific, the idea is that an application in Ruby ...
0 votes
2 answers
37 views

postfix with dovecot : many authentication failures

I have installed postfix with dovecot and after while i have found tons of authentication failures from internet. I have installed and configured fail2ban and every not authenticated IP is banned but ...
0 votes
1 answer
34 views

How can I convince postfix to send mail to my local maildir using dovecot lmtr?

I have installed dovecot and postfix on debian 12 and it is working but broken. I can connect to dovecot and see the existence of /var/mail/username/ on my server. My problem is simply that sending ...
1 vote
0 answers
37 views

How to make Postfix hand off emails via LMTP to Dovecot better (virtual vs relay)?

There are 2 ways how Postfix can hand off emails via LMTP. The first approach is recommended by Kyle Dent in his book about Postfix. He suggests it in cases when we want to store emails in a ...
2 votes
2 answers
5k views

How can I stress test my Postfix system without actually sending existing addesses mails?

I'd like to stress my Postfix servers, and I need to make a huge amount of sendings, but of course, I don't want to send spam to any real address, and I don't my IP's to be blacklisted. Is there any ...
0 votes
0 answers
45 views

Postfix/dovecot use external smtp server to send auto-reply

I want that dovecot vacation extension uses an external smtp server for sending the out of office (vacation) mails. Current setup: I use postfix for my incomming mails and dovecot for my imap, all ...
-1 votes
1 answer
173 views

Sending email with postfix on a specific IP address fails. Error 81126 with Gmail

Recently, I started to receive errors from Gmail: host gmail-smtp-in.l.google.com[142.250.110.27] said: 550-5.7.25 [X.X.X.X] The IP address sending this message does not have a 550-5.7.25 PTR record ...
2 votes
3 answers
1k views

I'm seeing performance problems with postfix accepting mail when the queue is already large, any suggestions?

I use postfix to do final delivery for a mail system I've written. So this postfix installation only accepts mail from me, and bounces. When the postfix queue is empty, it can accept a piece of mail ...
2 votes
0 answers
210 views

How to avoid Postfix sending emails without authentication even to users of the same domain

hopefully you could help me. I just installed postfix and I am trying to configure to avoid spam. The version I installed is 3.4.14 I am trying to configure posfix to have this behavior: From External ...
1 vote
0 answers
44 views

rspamd intermittently mark outgoing emails with HFILTER_HOSTNAME_UNKNOWN

We use rspamd to scan our outgoing emails so we can know if there's something wrong with our mail setup. Some of the email is sent through normal mailboxes, others through systems, for instance an ...
0 votes
1 answer
366 views

Postfix: Set connection rate limit exceeded per host

Is it possible to define the smtpd_client_connection_count_limit per domain in Postfix? I have a default setting of smtpd_client_connection_count_limit = 10, but I want to allow a higher limit for ...
2 votes
1 answer
10k views

postfix: lost connection after CONNECT/EHLO/unknown from unknown

seeing following error message while trying to send email via postfix on Centos 7 while I can receive and download messages not seeing any errors postfix/smtpd[24532]: connect from unknown[5.31.230....
31 votes
3 answers
58k views

How should I test Clam Anti-Virus?

I have setup a new email server and now I need to test that Clam Antivirus is scanning messages correctly. How should I do this in a safe and controlled way?
0 votes
1 answer
35 views

postfix access subdomain format

I need to allow a domain to bypass my RBL checks. I use: check_client_access hash:/etc/postfix/client_checks, That works fine except I needed to add outbound.protection.outlook.com. I dont' seem to ...
-3 votes
0 answers
44 views

Setting up mailserver with Postfix/Dovecot

I'm probably missing something glaringly obvious here, but it's driving me nuts. This week my mail server broke down, so I'm rebuilding one. I set this up YEARS ago, so I'm basically re-learning from ...
0 votes
1 answer
78 views

RHEL + how to know the limit of concurrent connections number per port?

how to know the number of concurrent connections per port on RHEL 7.x machines for instance, let say we connect to port 9080 with XXXX concurrent connections. wget http://server_mngmnt.jupiter.com:...
2 votes
3 answers
6k views

Postfix smtpd won't talk to saslauthd

I have an saslauthd setup to authenticate against PAM. It seems to do its stuff: root@sasltest:~# testsaslauthd -u quest -p #### -s smtp 0: OK "Success." I have libsasl 2.1.23, postfix 2.7.1. I ...
0 votes
1 answer
107 views

Can postfix enforce reject_unknown_helo_hostname before permit_sasl_authenticated?

I have a working postfix 3.5 relay where the config includes: smtpd_client_restrictions = permit_mynetworks, reject_unknown_client_hostname, permit smtpd_helo_required=yes ...
6 votes
4 answers
12k views

DKIM error: dkim=neutral (bad version) header.i=

Ive been struggling the last couple of hours with setting up DKIM on my Postfix/CentOS 5.3 server. It finally sends and signs the emails, but apparently Google still does not like it. The errors I'm ...
0 votes
1 answer
105 views

Resolve issues with DNSBLOG and b.barracudacentral.org

I am using postfix with DNSBLOG to prevent spam. The postfix main.cf is configured like: postscreen_dnsbl_sites = zen.spamhaus.org=127.0.0.[2..11]*3 b.barracudacentral.org=127.0.0.2*2 DNSBLOG is ...
2 votes
0 answers
22 views

postfix wrappermode depending on destination

My ISP accepts mail on port 465 thus requiring smtp_tls_wrappermode = yes. However, I also have another internal server, to which I forward mail on port 25 using STARTTLS, but with ...
0 votes
1 answer
34 views

Why does mailman replace non-Latin letters with crooked ones?

The essence of the problem is that when sending an html letter with formatted text inserted from another source containing non-Latin letters (for example, copied text from a web page in Polish), the ...
0 votes
0 answers
44 views

postfix MTA seemingly benign I/O Error : postqueue fatal: output write error: Input/output error

I am getting the following message in my syslog exactly every 30 seconds. Everything is working but words like "Fatal" and "Input/output error" cause me an inordinate amount of ...
0 votes
0 answers
55 views

Redirect mails to a different recipient

We have a server which is sending sheduled mails to an address which does not exists. This was a false configuration by a former coworker and we are unable to detect where it happens. So our idea was ...
0 votes
1 answer
5k views

RoundCube: Connection to storage server failed

This is probably the hardest challenge I have ever faced on Linux. I would never thought sending and receiving the ubiquitous Emails is such hell of a complication! Following this tutorial on Setup ...
1 vote
0 answers
64 views

Postfixadmin Kubernetes Debian 12

I have setup a kubernetes cluster on debian 12(first time), and i used the docker mailserver project to install the pods. So far so good, but now I can't seem to expose the 80 or 443 to a network that'...
1 vote
1 answer
1k views

Emails sent with postfix treated as spam, and sometimes not delivered at all

I'm trying to set up sending emails with SMTP on my VPS running Ubuntu 18.04. I'm using postfix, nodemailer. When I send from an [email protected], to a gmail account, it gets stuck in the gmail ...
2 votes
1 answer
58 views

Postfix: high delay in queue manager

Although this question has been asked before, there was no accepted answer (and the quality of answers was not good). For one site where I send emails to, the "in queue manager" delay metric ...
0 votes
1 answer
112 views

Can't receive messages in inbox of Thunderbird with Postfix and Dovecot

I have dovecot and postfix installed and working properly. I send messages to the server with postfix and Dovecot from clientnorbert@clientnorbert-1-2, with the email clientnorbert@ubuntumailsystem ...
0 votes
1 answer
5k views

NOQUEUE: reject: RCPT from 451 4.3.5 Server configuration

Unfortunately after some changes on master.cf and main.cf in postfix I'm getting these errors when I try to send out a e-mail. root@mail:/etc/postfix# tail -f /var/log/syslog | grep "rene.brakus@...
1 vote
1 answer
347 views

Deliver mails in Maildir in /var/spool/mail with Postfix

I search for hours without finding the solution and it drives me crazy. Is it possible to ensure, without using Procmail, that Postfix delivers emails in the form of Maildir {cur,new,tmp} in /var/...
0 votes
0 answers
274 views

How to upgrade postfix/dovecot/spamassassin/postscreen email server from Ubuntu 20.04 to Ubuntu 22.04?

I am running an Ubuntu 20.04 based LEMP Email server running Postfix, Dovecot, Postscreen, and SpamAssassin. I built the server using this Linuxbabe Guide, and followed the instructions and every ...
2 votes
2 answers
13k views

Postfix - Recipient Address Rejected on Incoming Mail Only

I am working on building a secure mail server for the first time using Postfix and Dovecot and I have encountered a problem that I cannot surpass. To avoid the email delivery in the spam box of ...
3 votes
1 answer
315 views

How to make postfix sign non-delivery notifications with DKIM?

I have set up my "postfix" server to sign outgoing messages with DKIM and verified that it works correctly for SMTP users using authentication. However, "non-delivery notifications"...
0 votes
2 answers
66 views

How to detect non-latin scripts in email subject?

On my mail server running Postfix, I want to reject mails using some non-latin scripts in their subject, in particular Arabic and Cyrillic since none of my users (family) speak languages that use them....
1 vote
1 answer
38 views

dovecot telnet localhost 143

I have problem with dovecot, when im trying telnet localhost 143 i got root@ubuntuserver:/etc/dovecot# telnet localhost 143 Trying 127.0.0.1... telnet: Unable to connect to remote host: Connection ...
1 vote
1 answer
418 views

Virtual domain variable in postfix/smtp_header_checks

What Postfix virtual domain variable should I use in outgoing header creation? Current server I'm running a database-driven virtual domain server managed by PostfixAdmin. I want to put statements in ...
2 votes
1 answer
157 views

Add original message id to headers in a postfix bounce

I'm running an OSticket support system that utilizes the Mailcow stack for email messaging. Everything is working fine, except for cases when we cannot email a ticket author due to mailbox issues on ...
0 votes
0 answers
27 views

Postfix/Postgrey/openDMARC: Bypass greylisting if DMARC check succeeds

I have set up Postfix so that it is using Amavis (in conjunction with Spamassassin and ClamAV), openSPF, openDKIM, and Postgrey, and I have recently added openDMARC to the configuration. All of them ...

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