Part 5. Mail traffic routing. Authorization on a upstream server.
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- Category: Mail Server
- Published: Tuesday, 21 May 2019 11:50
- Written by Super User
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Typically, you do not need to configure mail traffic routing. All messages will be routed automatically, according to MX records in the DNS of the recipient domain. But there are exceptions to this rule. Using the transport_maps option, you can explicitly specify the server to which the mail will be sent for the specific domain.
Let’s create file /etc/postfix/transport and insert into it the line:
test.local smtp:192.168.0.2
Let’s create an indexed map from this file:
postmap /etc/postfix/transport
Next, add a line to the main.cf file:
transport_maps = hash:/etc/postfix/transport
Let’s restart Postfix
service postfix restart
Now, all messages for users in the test.local domain will be sent to the server 192.168.0.2 and it will happen without any requests from the mail server.
Another reason is to configure routing is when the mail can not be sent directly to the recipient's server for some reason. In this case, you must use a higher-level server-the so-called mail relay.
This can be accomplished using the parameter relayhost.Assume that we need to send mail through a server named mail.test.local and through port 587 (SMTP submission port). To achieve this, add a line to the main.cf file:
relayhost = [mail.test.local]:587
After Postfix restart all messages will be routed to the mail.test.local.
There may be another problem at this stage. This will happen if the relay server requires authorization. To cjnfigure the login-password transmission you must do the following
Insert the following lines into the file main.cf :
# Enable Authentification
smtp_sasl_auth_enable = yes
# Specify a file with logins and passwords
smtp_sasl_password_maps=hash:/etc/postfix/sasl_passwd
#Disable anonymous authentication
smtp_sasl_security_options = noanonymous
Let’s create file /etc/postfix/sasl_passwd and insert to it:
mail.test.local user@test.local:password
where
mail.test.local is the server to on which we will log in
user@test.local:password Login:Password
Then execute the command:
postmap /etc/postfix/sasl_passwd
and restart Postfix
service postfix restart
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