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Paul Tomblin
Asked: 2012-08-01 09:54:52 +0800 CST

Forward all email for one domain to a single account or file, but deliver other domains properly

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I have a Linux server which uses Postfix for email. Its on a dynamic ip so I use the "relayhost" parameter to send outgoing mail through an ssh tunnel to another server on a static ip and from there it goes out to the real world. That's been working fine since about 1998 or so.

I'm currently developing some software for a client, and it sends email to various people in that client's organization based on information in a database. For my initial testing, I created fake people who all had email addresses like ptomblin+client1@{mydomain}.com, which worked fine and sent all the email to me. But now I'm working with a live database, and all the email addresses are for real people in the client's organization. I don't particularly want to send email to those people telling them that the system access they requested has been provisioned, so I'd like a way to redirect all email to that client's domain to either my email address or to a file.

linux

2 Answers

  1. Best Answer

    If I understand correctly, you want all the mail destinated to example.com be delivered to your mail address or a file, instead of being forwarded to the server specified in relayhost :

    step 1: Add example.com to mydestination in main.cf so that mail destinated to example.com is delivered locally .

    step 2: Setup a catchall for example.com and send all email to your mail address or a file. You can for example use postfix pcre to achieve this.

    Expanded step 2

    Using postfix pcre is only one way to achieve this among many others . According to this tutorial by garisson :

    1. Create a local user mylocaluser and it's mailbox or maildir

    2. Create a file named aliases-pcre with content :

      /@example\\.com$/ mylocaluser

      add the following lines to main.cf (if main.cf is in /etc/postfix):

      alias_database = hash:/etc/postfix/aliases
alias_maps = hash:/etc/postfix/aliases, pcre:/etc/postfix/aliases-pcre

    3. Restart postfix

    Now, all mail destinated to *@example.com should go to mylocaluser mailbox/maildir.

    Again, this is just an example. You can use any other method that best fits your needs. I tend to use pcre a lot because it allows regexp that are a bit more complex.

    However, the above would not work as you need virtual domain.

    Here's a minimal sample configuration :

    (main.cf)
alias_database = hash:/etc/aliases
local_recipient_maps = 
relayhost = myotherserver.example.com
virtual_alias_maps = pcre:/etc/postfix/aliases-pcre
virtual_alias_domains = example.com
mydestination = localhost

    File /etc/postfix/aliases-pcre

    /@example\.com$/ somelocaluser
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  2. Ok, Eric got me close to the right path, but not quite there. This is what I did:

    1. In /etc/postfix/main.cf:

      virtual_alias_domains = example.com
virtual_alias_maps = regexp:/etc/postfix/virtual_alias

    2. In /etc/postfix/virtual_alias

      /@example\.com/ ptomblin

    One postfix reload later and I was away to the races. (By the way, you don't need to do postmap on regular expression files, only hashs)

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