Postfix, Dovecot and catch-all

dovecotpostfix

I've set up my mail server using a guide from Digital Ocean, followed by another guide. So, now if I send mail to torvin@mydomain, it works.

Now I'm trying to set up a catch-all address for all undelivered mail. Things I've tried so far:

1) Replaced

local_recipient_maps = proxy:pgsql:/etc/postfix/pgsql-boxes.cf $alias_maps

line with this:

local_recipient_maps =
luser_relay = torvin

The result I see in the logs:

postfix/lmtp[32692]: D5AD540085: to=, relay=mail.mydomain[private/dovecot-lmtp], delay=0.21,
delays=0.17/0.01/0.01/0.02, dsn=5.1.1, status=bounced (host
mail.mydomain[private/dovecot-lmtp] said: 550 5.1.1
User doesn't exist:
thisisjustatest@mydomain (in reply to RCPT TO command))

2) Instead replaced

alias_maps = hash:/etc/aliases proxy:pgsql:/etc/postfix/pgsql-aliases.cf

with

alias_maps = hash:/etc/aliases pcre:/etc/aliases_pcre proxy:pgsql:/etc/postfix/pgsql-aliases.cf

And created /etc/aliases_pcre with the following content:

/.*/    torvin

Result is the endless loop of:

to=, relay=local, delay=0.01, delays=0/0/0/0,
dsn=5.4.6, status=bounced (mail forwarding loop for torvin@mydomain)

3) Instead tried

virtual_alias_maps = pcre:/etc/aliases_pcre

Now all my mail goes to torvin, and never gets delivered to any other existing users in the system.

Please help!

Best Answer

This is because /.*/ also includes torvin. I assume your proxy:pgsql: has information on this user, but pcre:/etc/aliases_pcre is looked before that. In this case, the easiest solution would be to reorder them. Also, a simple hash: database line @example.com torvin@example.com would do the same as your /.*/ PCRE approach.

Technical implementation aside, having such a catch-all on a domain with multiple users is a bad idea. There would not be ANY actual messages that would need attention. What you'd get is:

  • Spam for non-existent common addresses like sales@example.com. This is the most common.
  • Messages destined to someone else. Picture someone trying to send confidential information to Jane Smith on <j.smith@example.com>, but forgets the dot <jsmith@example.com> or mistypes it like <j.smiht@example.com>. Normally, the sender would receive a notification that the user doesn't exist, double check the email address and resend the message. With a catch-all, this doesn't happen. Instead, there's this torvin guy in an awkward and most likely illegal situation.

Both should be treated with a SMTP connection-stage rejection.

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