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Alias Tag Date DocType Hierarchy TimeStamp location CollapseMetaTable
Postfix
Server
Email
2021-09-10 Personal NonRoot
51.514678599999996
-0.18378583926867909
Yes

Parent:: Selfhosting, Alias Server, Cloud Server, Tools Server

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Configuring Postfix

title: Summary
collapse: open
This note goes through the installation of Postfix, an email-handling solution for servers.

style: number


Installation

Installation is simple and opens a dialogue box. Steps are described below:

  1. Install Postfix

sudo apt-get install -y postfix postfix-pgsql -y

  1. Configuration screen

Choose 'Internet Site'

  1. System mail name

Define a name and make a note of it for further use.


Generic configuration

title: Documentation
[Basic config](https://github.com/simple-login/app)

The basic configuration is run in detail below.

Main.cf

title: File path
/etc/postfix/main.cf

Edit the file whilst editing the following values:

  1. myhostname (current server)
  2. mydomain (associated domain)
  3. my origin (associated domain)
POSTFIX config file, adapted for SimpleLogin

smtpd_banner = $myhostname ESMTP $mail_name (Ubuntu) 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_tls_session_cache_database = btree:${data_directory}/smtpd_scache smtp_tls_session_cache_database = btree:${data_directory}/smtp_scache smtp_tls_security_level = may smtpd_tls_security_level = may

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

alias_maps = hash:/etc/aliases mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128 240.0.0.0/24

Set your domain here

mydestination = myhostname = app.mydomain.com mydomain = mydomain.com myorigin = mydomain.com

relay_domains = pgsql:/etc/postfix/pgsql-relay-domains.cf transport_maps = pgsql:/etc/postfix/pgsql-transport-maps.cf

HELO restrictions

smtpd_delay_reject = yes smtpd_helo_required = yes smtpd_helo_restrictions =

permit_mynetworks, reject_non_fqdn_helo_hostname, reject_invalid_helo_hostname, permit

Sender restrictions:

smtpd_sender_restrictions =

permit_mynetworks, reject_non_fqdn_sender, reject_unknown_sender_domain, permit

Recipient restrictions:

smtpd_recipient_restrictions =

reject_unauth_pipelining, reject_non_fqdn_recipient, reject_unknown_recipient_domain, permit_mynetworks, reject_unauth_destination, reject_rbl_client zen.spamhaus.org, reject_rbl_client bl.spamcop.net, permit

relay domains

title: File path
/etc/postfix/pgsql-relay-domains.cf

Below is the default config for the file (replace mydomain.com with relevant value):

postgres config

hosts = localhost user = myuser password = mypassword dbname = simplelogin

query = SELECT domain FROM custom_domain WHERE domain='%s' AND verified=true

UNION SELECT '%s' WHERE '%s' = 'mydomain.com' LIMIT 1;

transport maps

title: File path
/etc/postfix/pgsql-transport-maps.cf

Below is the standard declaration of the file (replace mydomain.com with the relevant value):

postgres config

hosts = localhost user = myuser password = mypassword dbname = simplelogin

forward to smtp:127.0.0.1:20381 for custom domain AND email domain

query = SELECT 'smtp:127.0.0.1:20381' FROM custom_domain WHERE domain = '%s' AND verified=true

UNION SELECT 'smtp:127.0.0.1:20381' WHERE '%s' = 'mydomain.com' LIMIT 1;

Generic commands

Restart the service

sudo systemctl restart postfix


Allow external connections

title: Documentation
[Fwd to external smtp](https://github.com/simple-login/app/discussions/612)

Incoming

  1. Ports

Ports (25, 465, 587) need to be opened by the firewall:

sudo ufw allow (port)/tcp

  1. Networks

Definition of permitted networks to restrict access (in Postfix config#Main cf).

  1. Submission/SMTPD
title: File path
/etc/postfix/master.cf

Options are coded in the file by default. Uncheck necessary directives.

  1. SSL cert

Postfix SSL certs need to match that of the server (in Postfix config#Main cf).

  1. SASL

Tutorial

Outgoing