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--- mail:postfix [2018-12-09 22:40] – old revision restored (2018-12-09 20:44) gabriel
+++ mail:postfix [2020-05-31 00:57] (current) – description gabriel
@@ Line 1: / Line 1: @@
 ====== Postfix ======
-Notes on Postfix configuration and tricks.
+Notes on Postfix configuration and other silly tricks.
 ===== Configuring Postfix with Gmail as an SMTP relay =====
+I currently run my external mail on a Google Apps account.  As a simple solution to allow me to send mail from several Linux systems, I have configured Postfix to use a specially configured Gmail account as a pseudo mail relay.
+To do this you really only need to make a few configuration changes to the default Postfix main.cf file that ships with the Debian package.
+<code>
+# See /usr/share/postfix/main.cf.dist for a commented, more complete version
+smtpd_banner = $myhostname ESMTP $mail_name (Debian/GNU)
+biff = no
+delay_warning_time = 4h
+readme_directory = no
+myhostname = localhost
+alias_maps = hash:/etc/aliases
+alias_database = hash:/etc/aliases
+myorigin = $myhostname
+mydestination = localhost, localhost.localdomain, localhost
+relayhost = [smtp.gmail.com]:587
+mynetworks = 127.0.0.0/8
+mailbox_size_limit = 0
+recipient_delimiter = +
+inet_interfaces = loopback-only
+smtp_sasl_auth_enable = yes
+smtp_sasl_password_maps = hash:/etc/postfix/sasl/gmail-passwdmap
+smtp_sasl_security_options = noanonymous
+smtp_tls_CAfile =  /etc/postfix/gmail-cacerts.pem
+smtp_use_tls = yes
+smtp_tls_loglevel=1
+smtp_tls_security_level=encrypt
+compatibility_level=2
+</code>
+==== Google CA certs ====
+You can retrieve the current Google CA certs from this page: https://support.google.com/a/answer/6180220?hl=en
+Store these certs as ''/etc/postfix/gmail-cacerts.pem''.
+==== Gmail app password ====
+You will also need to generate an app password to use with the account in Gmail.
+https://support.google.com/accounts/answer/185833?hl=en
+You can then configure this username and password in ''/etc/postfix/sasl/gmail-passwdmap'' accordingly:
+<code>
+[smtp.gmail.com]:587	my-smtp-relay@example.com:abcdefghijklmnop
+</code>
+Where //my-smtp-relay@example.com// is the Gmail account you will use and //abcdefghijklmnop// is your app password.  You will also need to use ''postmap(1)'' to create the Postfix binary map table for this file when you create or modify this file: <code>postmap  /etc/postfix/sasl/gmail-passwdmap</code>