A little bit confusing...

6 msg	One domain, one user account - aliases
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A little bit confusing...
\ Rocco Scappatura (14 Nov 2007)
. \ Hamilton Vera (14 Nov 2007)
. \ Rocco Scappatura (14 Nov 2007)

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Subject:	A little bit confusing...
Group:	Postfix-users
From:	Rocco Scappatura
Date:	14 Nov 2007

Hello,

I manage an SMTP relay server that receives email for a domain
'domain.it' an try to deliver it to a mail server that receives email
for 'domain.it'.

My local domain is 'av3.mydomain.it'.

I can't figure out why a lot of message from postmaster toward users of
my email domain that I'm responsible to, are sent (or apparently are
sent).

For example:

# cat /var/log/mail | grep postmaster
.
.
.
Nov 14 10:53:18 av3 postfix/qmgr[23784]: 37A0A75022E:
from=<postmaster>, size=257, nrcpt=1 (queue active)

av3:~ # cat /var/log/mail | grep 37A0A75022E
Nov 14 10:53:18 av3 postfix/cleanup[21989]: 37A0A75022E:
message-id=<20071114095318.37A0A75022E>
Nov 14 10:53:18 av3 postfix/qmgr[23784]: 37A0A75022E:
from=<postmaster>, size=257, nrcpt=1 (queue active)
Nov 14 10:53:18 av3 postfix/smtp[20128]: 37A0A75022E:
to=<tra.scherlin>, relay=10.30.32.7[10.30.32.7]:25,
delay=0.17, delays=0.07/0/0.07/0.03, dsn=5.0.0, status=undeliverable
(host 10.30.32.7[10.30.32.7] said: 550 tra.scherlin... No such
user (in reply to RCPT TO command))
Nov 14 10:53:18 av3 postfix/qmgr[23784]: 37A0A75022E: removed

Nov 14 10:53:18 av3 postfix/smtpd[19838]: NOQUEUE: reject: RCPT from
as-0-21.lns2-4c.kharkov.ukrtel.net[82.207.32.21]: 450 4.1.1
<tra.scherlin>: Recipient address rejected: undeliverable
address: host 10.30.32.7[10.30.32.7] said: 550 tra.scherlin...
No such user (in reply to RCPT TO command); from=<jquire>
to=<tra.scherlin> proto=SMTP helo=<goliat.espol.edu.ec>
Nov 14 10:53:18 av3 postfix/smtp[20128]: 37A0A75022E:
to=<tra.scherlin>, relay=10.30.32.7[10.30.32.7]:25,
delay=0.17, delays=0.07/0/0.07/0.03, dsn=5.0.0, status=undeliverable
(host 10.30.32.7[10.30.32.7] said: 550 tra.scherlin... No such
user (in reply to RCPT TO command))

And so..:

av3:~ # cat /var/log/mail | grep 37A0A75022E
Nov 14 10:53:18 av3 postfix/cleanup[21989]: 37A0A75022E:
message-id=<20071114095318.37A0A75022E>
Nov 14 10:53:18 av3 postfix/qmgr[23784]: 37A0A75022E:
from=<postmaster>, size=257, nrcpt=1 (queue active)
Nov 14 10:53:18 av3 postfix/smtp[20128]: 37A0A75022E:
to=<tra.scherlin>, relay=10.30.32.7[10.30.32.7]:25,
delay=0.17, delays=0.07/0/0.07/0.03, dsn=5.0.0, status=undeliverable
(host 10.30.32.7[10.30.32.7] said: 550 tra.scherlin... No such
user (in reply to RCPT TO command))
Nov 14 10:53:18 av3 postfix/qmgr[23784]: 37A0A75022E: removed

That is, It seems to me that I (postmaster) try to send a DNS (I
suppose) to inxistent email address 'tra.scherlin' to say
that some one has tried to send it an email, but that message has been
nevere delivered, because it do not exists (a clearly paradoxical
situation).

Moreover, postmaster is not notified that in truth someone has tried to
sent an email to an inexistent email address of a domain which he is
responsible!!

Where is the trick? Do I miss some logical step or is there any mistake?

Thanks,

rocsca