Postfix /etc/postfix/main.cf

Original 📋 Debian 9 (Stretch) 44 lines
/etc/postfix/main.cf
# 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

# TLS parameters
smtpd_tls_cert_file=/etc/ssl/certs/ssl-cert-snakeoil.pem
smtpd_tls_key_file=/etc/ssl/private/ssl-cert-snakeoil.key
smtpd_use_tls=yes
smtpd_tls_session_cache_database = btree:${data_directory}/smtpd_scache
smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache

# See /usr/share/doc/postfix/TLS_README.gz in the postfix-doc package for
# information on enabling SSL in the smtp client.

smtpd_relay_restrictions = permit_mynetworks permit_sasl_authenticated defer_unauth_destination
myhostname = b012e090f537
alias_maps = hash:/etc/aliases
alias_database = hash:/etc/aliases
mydestination = $myhostname, b012e090f537, localhost.localdomain, , localhost
relayhost = 
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mailbox_size_limit = 0
recipient_delimiter = +
inet_interfaces = all
inet_protocols = all

Copy & Paste

curl:
curl https://exampleconfig.com/api/v1/config/original/8802fc883e2a3c898c3fd49851bc53b2?hint=main.cf
wget:
wget -O main.cf https://exampleconfig.com/api/v1/config/original/8802fc883e2a3c898c3fd49851bc53b2?hint=main.cf

For AI Agents

<prompt><role>DevOps agent</role><source url='https://exampleconfig.com/api/v1/config/original/8802fc883e2a3c898c3fd49851bc53b2?hint=main.cf' /><config><app>Postfix</app><os>Debian 9 (Stretch)</os><location>/etc/postfix/main.cf</location><lines>44</lines><md5>8802fc883e2a3c898c3fd49851bc53b2</md5><sha256>1b0560ab68c07b5cbb5297a5c5481d4e657312f07eda52d05d852a842a5cddc1</sha256></config></prompt>

Paste into Claude, ChatGPT, or any AI assistant.

Install Postfix

Alpine Linux

sudo apk add postfix

Debian

sudo apt update && sudo apt install postfix

Red Hat Enterprise Linux

sudo yum install postfix

Ubuntu

sudo apt update && sudo apt install postfix

File Location

File Path
/etc/postfix/main.cf
Directory
/etc/postfix/
Significance
System-wide configuration directory
Description
Files in /etc/ contain system-wide configuration settings that affect all users.

FAQ

When should I use this main.cf?

Use it to restore a missing default, confirm what shipped, or diff against your current Postfix config.

How do I restore Postfix defaults?

Download the file, back up the current one in /etc/postfix/main.cf, replace it, then reload or restart Postfix.

Is main.cf safe for production?

It is the vendor default for Debian 9 (Stretch). Treat it as a baseline and review security and performance settings before production use.

How does this differ from other OS versions?

Defaults vary by distro and version. This copy matches Debian 9 (Stretch).

Can I use this for Postfix troubleshooting?

Yes. Diff it against yours to find drift, then restore only the sections you need.