E-mails with invalid receipient are delivered to administrator

[Bevan]

Hi,

I recently noticed that when sending an e-mail to an invalid receipient (for example "foo", without an '@' anywhere) using a Plesk server running Postfix, this email does not bounce but instead is delivered to the administrator of that server. The maillog shows the following:

Dec 2 22:02:28 somehost postfix/smtpd[20202]: 07661DA3C17B: client=ip-[...], sasl_method=PLAIN, sasl_username=sender@host.tld
Dec 2 22:02:28 somehost /usr/lib/plesk-9.0/psa-pc-remote[1829]: Internal error. Unable to parse e-mail address.
Dec 2 22:02:28 somehost /usr/lib/plesk-9.0/psa-pc-remote[1829]: Unable to get recipient-domain handlers from the database
Dec 2 22:02:28 somehost /usr/lib/plesk-9.0/psa-pc-remote[1829]: Internal error. Unable to parse e-mail address.
Dec 2 22:02:28 somehost /usr/lib/plesk-9.0/psa-pc-remote[1829]: Unable to get recipient-domain handlers from the database
Dec 2 22:02:28 somehost /usr/lib/plesk-9.0/psa-pc-remote[1829]: Internal error. Unable to parse e-mail address.
Dec 2 22:02:28 somehost /usr/lib/plesk-9.0/psa-pc-remote[1829]: Unable to get recipient-domain handlers from the database
Dec 2 22:02:28 somehost postfix/cleanup[20328]: 07661DA3C17B: message-id=<some-message-id>
Dec 2 22:02:28 somehost /usr/lib/plesk-9.0/psa-pc-remote[1829]: handlers_stderr: SKIP
Dec 2 22:02:28 somehost /usr/lib/plesk-9.0/psa-pc-remote[1829]: SKIP during call 'check-quota' handler
Dec 2 22:02:28 somehost spf filter[21512]: Starting spf filter...
Dec 2 22:02:28 somehost /usr/lib/plesk-9.0/psa-pc-remote[1829]: handlers_stderr: SKIP
Dec 2 22:02:28 somehost /usr/lib/plesk-9.0/psa-pc-remote[1829]: SKIP during call 'spf' handler
Dec 2 22:02:28 somehost postfix/qmgr[23802]: 07661DA3C17B: from=<sender@host.tld>, size=623, nrcpt=1 (queue active)
Dec 2 22:02:28 somehost postfix-local[21513]: postfix-local: from=sender@host.tld, to=admin@host.tld, dirname=/var/qmail/mailnames
[...]

The e-mail the administrator gets, then contains the following header lines:

X-Original-To: foo
X-No-Relay: not in my network
Delivered-To: admin@host.tld
To: foo

I think this is definately not the behaviour that you want.
- you don't want the administrator to read emails that weren't intended for him
- you want the sender of that mail to be informed about the delivery issues

Please review this behaviour.

Greetings,
Michael

PS: I'm using Plesk 11.0.9 #27 on Debian Squeeze 64bit.