SMTP server from exchange 2003 reacts very slow on SMTP commands


We have an Exchange 2003 server running on a SBS 2003 server. The server is accepting and sending mails.
Though when we test the mail server from we get very slow responses. So I tried to do the same commands local on the server (telnet localhost 25). Even there i get very slow responses.
The initial connection is very fast, the answer to HELO is very fast.
The mail is also fast. But when you do the rcpt command it takes about 5 seconds before you get a response. Since I don't know which impact this has on our incomming mails I would like to resolve this as quick as possible.

Thanks in advance.
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LeeDerbyshireConnect With a Mentor Commented:
Did you enable the 'Filter recipients who are not in the directory' checkbox in ESM Message Delivery\Repicient Filtering.  Did you then also configure the Tarpittime delay registry entry?

This is the only thing I can think of.
bednareklucAuthor Commented:
No, the installation is a complete fresh installation. SBS 2003 default configuration. After that all the updates where installed. And Exchange SP2 was installed. No further modifications where done.
As Lee has already pointed out - that is what happens as a part of any tarpitting changes. Therefore I don't think it will be having an impact on the reception of email messages.

What else is on this server?
AV perhaps? If so, has it been configured to exclude the Exchange directories?

bednareklucAuthor Commented:
Lee, You where correct, it seems to be that these are new settings from microsoft to improve security.
It should not affect regular mail reception, but if somybody tries to find out used mail adresses they get delays.
Thanks for the help
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