Postfix 01 - a basic installation

category: learnz/postfix · date: 2009-02-09 · source: old.linuxor.sk/MAIL/POSTFIX-HOWTOs/user17/howto-postfix.txt · theme: github

Postfix Mail Server Learning · Next: Debian 4 - Postfix + SASL + TLS

The Slovak original of this document: Postfix 01 - základná inštalácia (slovensky).

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********* install postfix **************************************
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#apt-get install postfix
# /etc/init.d/postfix [start|stop|restart]
#cat /var/log/mail.log

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********* install courier-imap *********************************
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# apt-get install courier-imap
# /etc/init.d/courier-imap [start|stop|restart]

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********* install courier-pop **********************************
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# apt-get install courier-pop
# /etc/init.d/courier-pop [start|stop|restart]
# /etc/init.d/courier-authdaemon [start|stop|restart]

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********* config postfix ***************************************
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# nano /etc/postfix/main.cf

myhostname = mail.client02.example
mydomain = client02.example
myorigin = $mydomain
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
mydestination = $mydomain, $myhostname, localhost.$mydomain
relayhost =
mynetworks = 127.0.0.0/8 10.10.1.0/24 192.168.0.0/24
mailbox_size_limit = 51200000
recipient_delimiter = +
inet_interfaces = all
home_mailbox = Maildir/

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********* creating the mail directory for the users ************
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#cd /home/user
#maildirmake Maildir
#chown user.user Maildir/ -Rf

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********* automatic creation of Maildir for adduser ************
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# cd /etc/skel
# maildirmake Maildir

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********* install ClamaV ***************************************
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## adding the sources to apt

# nano /etc/apt/sources.list

## clamav
deb http://ftp2.de.debian.org/debian-volatile etch/volatile main

# apt-get install clamav clamav-base

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********* install MailScanner **********************************
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# apt-get install mailscanner

# nano /etc/postfix/main.cf

header_checks = regexp:/etc/postfix/header_checks

# nano /etc/postfix/header_checks

/^Received:/ HOLD

# nano /etc/MailScanner/MailScanner.conf

%org-name% = BigCorp2
%org-long-name% = BigCorp2
%web-site% = www.bigcorp2.example
%report-dir% = /etc/MailScanner/reports/sk
Run As User = postfix
Run As Group = postfix
Incoming Queue Dir = /var/spool/postfix/hold
Outgoing Queue Dir = /var/spool/postfix/incoming
MTA = postfix

Virus Scanners = clamav
Quarantine Silent Viruses = yes
Still Deliver Silent Viruses = yes
Notify Senders = yes
Filename Subject Text = {Zly nazov suboru?}
Content Subject Text = {Nebezpecny obsah}
Size Subject Text = {Velkost emailu}
Phishing Modify Subject = yes
Phishing Subject Text = {Podvodny mail?}
Attachment Encoding Charset = ISO-8859-2
Log Silent Viruses = yes

# nano /etc/default/mailscanner

run_mailscanner=1

# chown postfix:postfix /var/lock/subsys/MailScanner/
# chown postfix:postfix /var/run/MailScanner/
# chown postfix:postfix /var/lib/MailScanner/
# chown postfix:postfix -R /var/spool/MailScanner/

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********* useful commands **************************************
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## removing several messages at once
mailq | grep 'hladanyretazec' | awk '{print substr($1,1,10)}' | postsuper -d -

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Current practice (checked 2026-10)

noteThe article above is kept as it was written in 2009. This section lists what has changed since and what to do instead today.

Service control: the article uses /etc/init.d/postfix [start|stop|restart]. Debian has used systemd since Debian 8, so the same is done with systemctl restart postfix, systemctl restart courier-imap and so on.
No TLS anywhere: the main.cf shown has no TLS settings and Courier POP3/IMAP is installed without TLS, so mail and passwords cross the network in cleartext. Set smtpd_tls_security_level = may and smtp_tls_security_level = may with a real certificate, and offer POP3/IMAP only over TLS; RFC 8314 asks for TLS 1.2 or later between mail clients and servers and treats cleartext access as obsolete.
Relaying by mynetworks only: this is still fine for a trusted LAN. Users outside those networks should not be added to mynetworks; they send through an authenticated submission service on port 587 (STARTTLS) or 465 (implicit TLS), which RFC 6409 and RFC 8314 define for that purpose.
hash: tables: alias_maps = hash:/etc/aliases needs Berkeley DB, which some Linux distributions are removing. The Postfix 3.11 release announcement points to NON_BERKELEYDB_README for migrating hash: to lmdb: or cdb:; check postconf default_database_type on your system.
debian-volatile: the etch/volatile source no longer exists. The volatile suite was replaced by stable-updates starting with Debian squeeze, and ClamAV updates for a stable release arrive through that suite.
MailScanner: the mailscanner package was removed from Debian in 2011, so apt-get install mailscanner no longer works; upstream continues as MailScanner v5 on GitHub and has to be installed from there. The interfaces Postfix itself documents for content inspection are content_filter (after-queue), smtpd_proxy_filter (before-queue) and Milter.
Notify Senders = yes: sender addresses of viruses and spam are forged, so these notices go to people who never sent the message. Set it to no.
Removing messages from the queue: substr($1,1,10) assumes 10-character queue IDs, which is not guaranteed (queue IDs vary in length, and enable_long_queue_ids = yes makes them longer). Since Postfix 3.1 the queue can be listed as JSON and filtered safely, as below.

bash

$ # postqueue -j | jq -r 'select(.sender | test("searched-string")) | .queue_id' | postsuper -d -

Sources: