320x200: /* Running the relay on a different port */

2018-05-18T09:52:21Z

Running the relay on a different port

← Older revision		Revision as of 09:52, 18 May 2018
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	* restart '''both''' Postfix servers		* restart '''both''' Postfix servers
	service postfix restart		service postfix restart

			=== Troubleshooting ===
			* If problems, the places to look for useful info are:
			/var/log/mail.info # on relay and sat servers
			mail # to check reports received by Postix on sat when using sendmail



	[[Category:Email]]		[[Category:Email]]

320x200: /* Troubleshooting */

2018-05-18T09:50:39Z

Troubleshooting

← Older revision		Revision as of 09:50, 18 May 2018
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	service postfix restart		service postfix restart

	~~=== Troubleshooting ===~~
	* If problems, the places to look for useful info are:
	~~/var/log/mail.info # on relay and sat servers~~
	~~mail # to check reports received by Postix on sat when using sendmail~~

	[[Category:Email]]		[[Category:Email]]

320x200 at 13:03, 13 April 2018

2018-04-13T13:03:00Z

← Older revision		Revision as of 13:03, 13 April 2018
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	mail # to check reports received by Postix on sat when using sendmail		mail # to check reports received by Postix on sat when using sendmail

	[Category:Email]		[[Category:Email]]

320x200 at 13:02, 13 April 2018

2018-04-13T13:02:45Z

← Older revision		Revision as of 13:02, 13 April 2018
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	/var/log/mail.info # on relay and sat servers		/var/log/mail.info # on relay and sat servers
	mail # to check reports received by Postix on sat when using sendmail		mail # to check reports received by Postix on sat when using sendmail

			[Category:Email]

320x200: Created page with "'''Purpose:''' To make an existing working Postfix email server work as a relay for another Postfix email server. '''Note:''' This documentation assumes there is already a wo..."

2018-04-13T13:02:06Z

Created page with "'''Purpose:''' To make an existing working Postfix email server work as a relay for another Postfix email server. '''Note:''' This documentation assumes there is already a wo..."

New page

'''Purpose:''' To make an existing working Postfix email server work as a relay for another Postfix email server.

'''Note:''' This documentation assumes there is already a working Postfix server able to send receive email via SASL authentication and with properly configured TLS.

== Relay and Satellite configuration ==
=== Main Postfix relay server (relay.server.net) ===
* Create user that will be used for the other Postfix server to authenticate itself:
adduser relay
* Prevent ssh access for the user, in /etc/ssh/sshd_config, add:
DenyUsers relay
* Test that the relay user can indeed send email
su relay
echo "Subject: this is a test" | /usr/sbin/sendmail -v some@where.nice
* If all cool you can proceed :)

=== Postfix server(s) that need to have their email relayed (sat.server.net) ===
* Install postfix as ''Satellite system'' so it can send emails to the relay server (if postfix was already installed and you need to '''reset''' the current config you can use `dpkg-reconfigure postfix`)
* Set the FQDN of the server that needs to have its emails relayed:
sat.server.net
* Give the FQDN of relay server:
[relay.server.net]:25
* Rest of config is up to specific taste, but '''do not use address extension'''.
* Configure Postfix to use the smarthost with TLS by adding the following to /etc/postfix/main.cf:
relayhost = [relay.server.net]:25 # THIS ONE SHOULD ALREADY BE IN
smtp_tls_security_level = encrypt
smtp_sasl_auth_enable = yes
smtp_sasl_password_maps = hash:/etc/postfix/smtp_auth
smtp_sasl_security_options = noanonymous
* Create the file /etc/postfix/smtp_auth to specify the account created in previous section:
[relay.server.net]:25 relay:password
* Prepare file for postfix to use it (if you change it you need to re-run postmap):
chmod 600 /etc/postfix/smtp_auth
postmap /etc/postfix/smtp_auth
* restart Postfix:
service postfix restart
* try to send a mail from the sat server:
echo "Subject: this is a test from sat" | /usr/sbin/sendmail -v some@where.nice

== PRO tips ==
=== Running the relay on a different port ===
Sometimes the satellite server may be prevented to establish an outgoing connection with the relay server on port 25 or submission port 587. The workaround is to make the relay also accept incoming connection on another non-blocked port.
* On the '''relay''' server, allow listening on port 12345, edit /etc/postfix/master.cf, and below smtp entry, add:
12345 inet n - y - - smtpd
* On the '''satellite ''' server, edit /etc/postfix/main.cf and update the relay info:
relayhost = [relay.server.net]:12345
* On the '''satellite ''' server, edit /etc/postfix/smtp_auth and also update the relay info:
[relay.server.net]:12345 relay:password
postmap /etc/postfix/smtp_auth
* restart '''both''' Postfix servers
service postfix restart

=== Troubleshooting ===
* If problems, the places to look for useful info are:
/var/log/mail.info # on relay and sat servers
mail # to check reports received by Postix on sat when using sendmail

Postfix Relay - Revision history

320x200: /* Running the relay on a different port */

320x200: /* Troubleshooting */

320x200 at 13:03, 13 April 2018

320x200 at 13:02, 13 April 2018

320x200: Created page with "'''Purpose:''' To make an existing working Postfix email server work as a relay for another Postfix email server. '''Note:''' This documentation assumes there is already a wo..."