Hi. I'm currently having a problem with SMTP relay on ZCS 8.0.3, since I updated from 8.0.2.

My mail server is inside a network(172.18.2.0/24) where other servers are. One of them, the web server(172.18.2.4) runs some web apps in PHP which usually send emails through the ZCS server without authentication.This worked OK with 8.0.2, but since I updated to 8.0.3 none of my web apps are able to send mail. I wrote a test with phpmailer; in debug mode, it outputs the following:

Code:
SMTP -> FROM SERVER:220 MAILSERVER.DOMAIN.COM ESMTP Postfix 
SMTP -> FROM SERVER: 250-MAILSERVER.DOMAIN.COM 250-PIPELINING 250-SIZE 10240000 250-VRFY 250-ETRN 250-AUTH PLAIN LOGIN 250-AUTH=PLAIN LOGIN 250-ENHANCEDSTATUSCODES 250-8BITMIME 250 DSN 
SMTP -> FROM SERVER:250 2.1.0 Ok 
SMTP -> FROM SERVER:554 5.7.1 : Recipient address rejected: Access denied 
SMTP -> ERROR: RCPT not accepted from server: 554 5.7.1 : Recipient address rejected: Access denied
The configuration for phpmailer is:

PHP Code:
$mail = new PHPMailer(true);
$mail->IsSMTP();
$mail->SMTPAuth false;
$mail->SMTPSecure "ssl";
$mail->Host "172.18.2.6";
$mail->Port 465;
$mail->SetFrom("webmaster@DOMAIN.COM","Webmaster");
$mail->Sender "webmaster@DOMAIN.COM";
$mail->AddReplyTo("webmaster@DOMAIN.COM","Webmaster");
$mail->AddAddress("USER@DOMAIN.COM","USER@DOMAIN.COM");
$mail->Subject $subject;
$mail->MsgHTML($body);
$mail->SMTPDebug 2;
$mail->Send(); 
At the same time, in /var/log/maillog, I get the following:

May 15 15:07:35 adriana postfix/smtps/smtpd[11298]: connect from unknown[172.18.2.4]
May 15 15:07:35 adriana postfix/smtps/smtpd[11298]: Anonymous TLS connection established from unknown[172.18.2.4]: TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)
May 15 15:07:35 adriana postfix/smtps/smtpd[11298]: NOQUEUE: filter: RCPT from unknown[172.18.2.4]: <webmaster@DOMAIN.COM>: Sender address triggers FILTER smtp-amavis:[127.0.0.1]:10026; from=<webmaster@DOMAIN.COM> to=<USER@DOMAIN.COM> proto=ESMTP helo=<WEB.DOMAIN.COM>
May 15 15:07:35 adriana postfix/smtps/smtpd[11298]: NOQUEUE: reject: RCPT from unknown[172.18.2.4]: 554 5.7.1 <USER@DOMAIN.COM>: Recipient address rejected: Access denied; from=<webmaster@DOMAIN.COM> to=<USER@DOMAIN.COM> proto=ESMTP helo=<WEB.DOMAIN.COM>
May 15 15:07:35 adriana postfix/smtps/smtpd[11298]: lost connection after RCPT from unknown[172.18.2.4]
May 15 15:07:35 adriana postfix/smtps/smtpd[11298]: disconnect from unknown[172.18.2.4]

The address of the mail server is 172.18.2.6. In the server network, WEB.DOMAIN.COM resolves to 172.18.2.4. "zmcontrol -v" outputs "Release 8.0.3_GA_5664.RHEL6_64_20130305090204 CentOS6_64 FOSS edition."

The value of zimbraMtaMyNetworks is "127.0.0.0/8 172.18.2.0/24" (without quotes). That value gets reflected in main.cf & in amavisd.conf

I've tried changing configuration, rebooting, restarting postfix & amavisd, but nothing works. For external mail, the server works properly, so the problem is only for local relay.

Hope someone can help me. Thanks in advance.