RE: Relay problem in Exchange


Thank for you update.

Based on my test, the SMTP Proxy Server is open for relay. But I want to
explaine when you use some third-party tools to test SMTP servers for
relay, the SMTP server may seem to fail the test and your Microsoft SMTP
product may seem to be open for relay, although it is not. This is because
the SMTP server may not immediately reject the e-mail message. Instead, the
SMTP server processes the e-mail message and then sends a non-delivery
report (NDR).
More info please refers to the following article:

SMTP relay behavior in Windows 2000, Windows XP, and Exchange Server

So I suggest your perform the tests mentioned in above KB to verify whether
your exchange server is open for relay.

Hope this helps. Have a nice day!

Best Regards,

Chace Zhang (MSFT)

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