11

I've a Ubuntu 9.04 server installation which is hosting a small number of websites (currently two, and will remain in single figures). The email requirements for the server are very limited - to send outgoing emails and forward all incoming emails to a mailbox on another server - most likely Google.

I've installed postfix and the outgoing mail is working fine. How do I configure Postfix to forward all incoming mail? If I send it to a googlemail address are there any special considerations? Finally how difficult is it to incorporate basic spam filtering into the forwarding mechanism?

13

This is called a "catch all"

Mapping is done using /etc/postfix/virtual file.

vi /etc/postfix/virtual

Append code as follows, replacing domain and emailusername with actual values:

@yourdomain.com emailusername

Save and close the file. Run following command:

postmap /etc/postfix/virtual

Also make sure you have following line in /etc/postfix/main.cf file:

virtual_alias_maps = hash:/etc/postfix/virtual

If you just added above, line reload postfix:

service postfix reload

From http://www.cyberciti.biz/faq/howto-setup-postfix-catch-all-email-accounts/

  • Brilliant stuff. This helped me too. Thanks Matt! – Mike B Dec 1 '09 at 6:16
5

You need virtual aliases. Something like:

virtual_alias_domains = foo.com, bar.com
virtual_alias_maps = hash:/etc/postfix/virtual

where /etc/postfix/virtual contains:

@foo.com    you@gmail.com
@bar.com    you@gmail.com

run postmap /etc/postfix/virtual to create the database from the map file and postfix reload to re-read the configuration. The virtual table is quite flexible -- you can match specific addresses or whole domains and forward mail to multiple addresses.

Note: Do not list the extra domains in $mydestination! See the docs for more detail.

No special considerations I can think of when sending to GMail addresses. One optional neat trick is to send mail for each domain to a separate address and have GMail automatically label it accordingly. Forward mail for foo.com to you+foo.com@gmail.com and bar.com to you+bar.com@gmail.com and corresponding filters. See this GMail blog post for more.

I haven't tried but one method to filter spam is to incorporate SpamAssassin. A Google for this turns up quite a few handy-looking guides.

0

Isn't it simpler to use 'always_bcc = name@domain.com' in main.cf? Denes

0

Note that when using virtual aliases or mail forwarding, Postfix tends to retain the envelope sender from the original message. This causes problems for Gmail and others that use SPF:

Received-SPF: softfail (google.com: domain of transitioning ***@***.com does not
    designate *** as permitted sender);

I haven't found any good solution for this, but here's a hack to sort-of-fix-it:

  1. Create a new file /etc/postfix/sender_canonical:

    /.*/    postmaster
    
  2. postmap /etc/postfix/sender_canonical

  3. Add some lines to /etc/postfix/main.cf:

    sender_canonical_classes = envelope_sender
    sender_canonical_maps = regexp:/etc/postfix/sender_canonical
    
  4. service postfix reload

  5. Send email from an external source and verify that Return-Path contains your postmaster@*** address

Warning: This replaces the envelope sender for all messages passing through your server, which may have unintended side-effects. The message From headers should not be modified by this however, so sender addresses should still display correctly.

  • How to configure sender_canonical to set a "From", I need to forward all incoming email using static email in "From" header, it is because I am using a relay that only can send email from the only email which are added there. – A.Aleem11 Oct 12 '18 at 6:42

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