I use a third party Spam filter / email archive company. All of our inbound and outbound traffic goes through this companies servers. Our MX record points to them, they filter and archive and then send the mail to us. In their setup instructions, it states that I need to lock down my firewall to restrict inbound SMTP traffict to ONLY their server's IP addresses/
Excerpt from their setup instructions -
"Inbound SMTP Restrictions:
Please wait 72 hours after changing your MX record
to allow full propagation across the Internet.
Next, restrict inbound port-25 SMTP traffic on your
firewall or mail server(s) to only accept mail from the
FrontBridge data centers as shown below."
and then it lists their IP addresses to use.
The problem is, I can't find anyone who knows how to do that. I have a Cisco Pix 515 firewall. Any suggestions would be appreciated. We are running MS Exchange 2003.