We have our mail go through Postini prior to being directed to our server. I would like to configure our 2007 exchange server so that it only accepts mail from the IP of the Postini servers. Can I configure the recevie connector with the IP address ofthe Postini server to only accept mail from that source? Since this server is in our internal network and has a private IP address, will I be able to add the Internet IP address for out Postini server? The server sits behind a router, so I'm not sure if the exchange server sees everything as if it is coming from the internal IP on the router or if it will actually see the internet IP address. Can someone let me know if this is doable? A more secure solution is probably to buy a firewall, configure a firewall rule but I'm not ready/able to put out the $$$ at this time for that piece of hardware.

Yes this is not only an option, but recommended. I believe postini has a doc with the exact IP ranges to use depending on what postini "system" you are using. I'll update this post if I find the link I'm thinking of.

Look at page 13 and 14 and 64. This should answer your question. http://www.postini.com/webdocs/outbound/en/outbound_config_en.pdf

I was able to set the inbound connector and users are seeing a marked reduction in the number of emails not coming through postini. (e.g.one personwas getting over 600 per day and it was reduced to less than 60) We are adding a cisco firewall and will filter at the firewall as well. Thanks. Jim