SBS 2003 Exchange Server: No emails

[Wiro]

I have a problem on a SBS 2003 exchange server.

1. A user does not receive emails from all over the world!
2. When I write to several people to this area, they do not get my message!

The SMTP log shows that there is a cut-off:
RCPT, -, TO: Recipient's email address ,
QUIT, -, mx.internetdsl.pl (its an example, there are other ad)

No transfer of DATA!

[Nihir]

What is your configuration? Is your exchange server mail domain (MX record)?
You use the pop3 connector? Your client send their mail via internal exchange (no pop account configured on outlook)? How the domain name, if not indiscreet?

[Wiro]

What is your configuration? HP ProLiant - SBS 2003
Is your exchange server mail domain (MX record)? yes - MX records are configured correctly so nobody mails.
You use the pop3 connector? no - it is forbidden (By ISP)
Your client send their mail via internal exchange (no pop account configured on outlook)? No Account pop - directly connected to Exchange
how the domain name, if not indiscreet ? xyz.in

[Nihir]

No antivirus or firewall on the server, particularly that of SBS? DNS side, nothing wrong? Everyone uses the server, which has its forwarders to those of ISP?

[Wiro]

Firewall - but if the ports are open for traffic.
Antivirus - yes - uninstalled and reinstalled tested - same problem.
DNS - yes those of ISP as forward-But the problem is to find the address and the connection is cut off without explanation.

[Nihir]

Firewall hardware? software? A single NIC on the server? No error message when the delivery does not arrive? Say that the queues to exchange?