FreeBSD 8.1
IRedMail 0.7.4
Mysql version

hostname = mydomain.ru
mydomain = mydomain.ru
other my domain = mydomain2.ru
problem domain = problem.ru

E-mail from the domain problem.ru come from my domain name (mydomain.ru)! E-mail sent from the address mag277@problem.ru

Return-Path: <mag277@problem.ru>
Delivered-To: om@mydomain2.ru
Received: from mydomain.ru (localhost [127.0.0.1])
by mydomain.ru (Postfix) with ESMTP id 9FFB3ACBA0
for <om@mydomain2.ru>; Thu, 15 Mar 2012 19:43:52 +0700 (NOVT)
X-Virus-Scanned: amavisd-new at mydomain.ru
Received: from mydomain.ru ([127.0.0.1])
by mydomain.ru (mydomain.ru [127.0.0.1]) (amavisd-new, port 10024)
with ESMTP id Kx6YdrpD1Zpx for <om@mydomain2.ru>;
Thu, 15 Mar 2012 19:43:47 +0700 (NOVT)
X-Original-Helo: oscar2.problem.ru (iRedMail: http://www.iredmail.org/)
Received: from oscar2.problem.ru (oscar2.problem.ru [78.***.142.***])
by mydomain.ru (Postfix) with ESMTP id 197B4ACB83
for <OM@mydomain2.RU>; Thu, 15 Mar 2012 19:43:47 +0700 (NOVT)
Received: from oscar2.problem.ru (localhost [127.0.0.1])
by oscar2.problem.ru (Postfix) with ESMTP id 0F4399B493;
Thu, 15 Mar 2012 19:43:56 +0700 (NOVT)
Received: from oper.mag277.problem.ru (oper.mag277.problem.ru [10.10.47.200])
(using TLSv1 with cipher AES256-SHA (256/256 bits))
(No client certificate requested)
by oscar2.problem.ru (Postfix) with ESMTPS id C711B9B48D;
Thu, 15 Mar 2012 19:43:55 +0700 (NOVT)
Date: Thu, 15 Mar 2012 19:43:52 +0700
From: =?windows-1251?B?zODj4Ofo7SC5Mjc3?= <mag277@*mydomain.ru*>
Organization: =?windows-1251?B?zs7OICLQ7uft6PbgLTEi?=
To: OM@mydomain2.RU, HLEB_OM@otherdomain.RU
Message-ID: <1586055123.20120315194352@mag277>
Subject: AutoZaka
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="----------631ED22F2B460884"
X-Virus-Scanned: ClamAV using ClamSMTP

how is this possible?

This log:
Mar 15 19:43:47 mydomain postfix-policyd-sf: rcpt=940, whitelist=update, host=78.***.142.*** (oscar2.problem.ru), from=mag277@problem.ru, to=om@mydomain2.ru, size=3240
Mar 15 19:43:47 mydomain postfix/smtpd[35030]: 197B4ACB83: client=oscar2.problem.ru[78.***.142.***]
Mar 15 19:43:47 mydomain postfix/cleanup[35032]: 197B4ACB83: message-id=<1586055123.20120315194352@mag277>
Mar 15 19:43:47 mydomain postfix/qmgr[1138]: 197B4ACB83: from=<mag277@problem.ru>, size=3502, nrcpt=1 (queue active)
Mar 15 19:43:47 mydomain postfix/smtpd[35030]: disconnect from oscar2.problem.ru[78.***.142.***]
Mar 15 19:43:52 mydomain postfix/smtpd[35036]: connect from localhost[127.0.0.1]
Mar 15 19:43:52 mydomain postfix/smtpd[35036]: 9FFB3ACBA0: client=localhost[127.0.0.1]
Mar 15 19:43:52 mydomain postfix/cleanup[35032]: 9FFB3ACBA0: message-id=<1586055123.20120315194352@mag277>
Mar 15 19:43:52 mydomain postfix/smtpd[35036]: disconnect from localhost[127.0.0.1]
Mar 15 19:43:52 mydomain postfix/qmgr[1138]: 9FFB3ACBA0: from=<mag277@problem.ru>, size=3919, nrcpt=1 (queue active)
Mar 15 19:43:52 mydomain amavis[34379]: (34379-07) Passed CLEAN, LOCAL [78.***.142.***] [78.***.142.***] <mag277@problem.ru> -> <om@mydomain2.ru>, Message-ID: <1586055123.20120315194352@mag277>, mail_id: Kx6YdrpD1Zpx, Hits: -9.83, size: 3502, queued_as: 9FFB3ACBA0, 5550 ms
Mar 15 19:43:52 mydomain postfix/smtp[35033]: 197B4ACB83: to=<om@mydomain2.ru>, relay=127.0.0.1[127.0.0.1]:10024, delay=5.7, delays=0.1/0.02/0.01/5.6, dsn=2.0.0, status=sent (250 2.0.0 from MTA([127.0.0.1]:10025): 250 2.0.0 Ok: queued as 9FFB3ACBA0)
Mar 15 19:43:52 mydomain postfix/qmgr[1138]: 197B4ACB83: removed
Mar 15 19:43:52 mydomain postfix/pipe[35037]: 9FFB3ACBA0: to=<om@mydomain2.ru>, relay=dovecot, delay=0.22, delays=0.05/0.04/0/0.13, dsn=2.0.0, status=sent (delivered via dovecot service)
Mar 15 19:43:52 mydomain postfix/qmgr[1138]: 9FFB3ACBA0: removed