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Accepting e-mail only from a specified IP address range

Hi all. Anyone able to tell me how to configure Exchange 2003 Server (or IIS?) to accept e-mail only from a specific IP address range. The range is in the format of 64.18.0.0/20. I want all other e-mail from any ohter IP address or range to be rejected. This is part of an anti-spam solution. Ideally, this mail will be rejected with an error message that makes senders think the server is not available or valid.

Thanks very much!!

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Sembee

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mikeprotech

ASKER

Simon - Thanks very much. I set it and will see if mail is still coming through properly from the range allowed. I don't need to apply the Connection filter in the Genreal tab of that screen? Again, thanks!!

Sembee

If you configure Exchange as I have outlined then you don't need to activate the connection filter.

However the other way to configure this option is to use "Connection Filtering" as part of the "Message Delivery" properties.

Both methods achieve the same result - I would use the latter method if I was doing it on multiple servers - all you have to do is enable connection filtering on all servers then configure it in a single place to get the entire org.

Simon.

mikeprotech

ASKER

Simon, it appears to be working well and will accept the answer, again with thanks. Just curious...do you know what error message will the sender of rejected e-mail receive?

Mike

Sembee

The NDR will be generated at the other end - they will probably get a connection refused. If you have made the change, try telnetting to port 25 on your external IP address from outside and see what happens:

telnet ip.add.re.ss 25

Simon.

mikeprotech

ASKER

Simply got a "Connection failed" message, which is more than good enough for what we need. Thanks Simon, and have a great New Year.

Mike