= Postfix Relaying =

Postfix is capable of relaying to other [[Email/SMTP|SMTP]] mail servers, either unconditionally or conditional on the destination.

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== Example ==

The `relay` instruction in a `transport(5)` file causes mail to be relayed to another SMTP server. For example:

{{{
localhost            local
.localdomain         local
*                    relay:[smtp.gmail.com]:587
}}}

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== Configuration ==

Use of a relay server often requires [[Postfix/Authentication|authentication]] and [[Postfix/Encryption|encryption]].

As an example, for GMail, try:

{{{
smtp_sasl_auth_enable = yes
smtp_sasl_security_options = noanonymous
smtp_sasl_password_maps = lmdb:/etc/postfix/sasl/sasl_passwd
smtp_tls_security_level = encrypt
smtp_tls_CAfile = /etc/ssl/certs/ca-certificates.crt
}}}

`/etc/postfix/sasl/sasl_passwd` should look like:

{{{
[smtp.gmail.com]:587 alias@gmail.com:wwwwxxxxyyyyzzzz
}}}

Run `postmap /etc/postfix/sasl/sasl_passwd` and a hashed file will be produced. If your `postmap(1)` does not use LMDB, replace the `lmdb:` with whatever algorithm ''was'' used.



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