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Cruachan
Asked: 2009-08-03 08:47:06 +0800 CST

simple postfix configuration - forward all incoming email to single address

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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?

ubuntu postfix gmail

4 Answers

  1. Best Answer

    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/

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  2. 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    [email protected]
@bar.com    [email protected]

    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 [email protected] and bar.com to [email protected] 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.

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  3. Isn't it simpler to use 'always_bcc = [email protected]' in main.cf? Denes

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  4. 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.

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