HELP - Exchange & Cisco 1700 Lockdown from SPAM

Hello everyone,


I want to thank everyone in advance for any information you provide.
I'm going to be as straigh forward as possible and give as much
detail
as possible.


We are running Windows 2000 SBS with Exchange and I have recently
moved my SPAM scanning externally outside of our building, through a
third-party SPAM scanning company called SpamSoap.


The issue that I am having foolows:
The scanner is working correctly and stopping almost all of the SPAM.
However, someone is directly mailing to our IP address; as our IP is
static we can not change it. SpamSoap recommends locking down our
exchange server to only except mail from a certain IP range they give
us. This is the problem, I don't know how to put these IP addresses
into exchange, and/or my Cisco 1700 router.


Does anyone know how to complete this? Is this true and possible to
be done?
Thanks again for looking and giving any thoughts you might have!
Mickie


.