lextm:I hope you have a firewall behind the IIS server and use it to filter out uninvited IP addresses instead of IIS IP restrictions.
Generally speaking a dedicated firewall performs such tasks better and allows IIS to focus on other activities.
Good point. My plan is a DMZ with the front firewall passing traffic on 443 and the rear firewall only passing 8009 traffic (connector default port). The IIS IP restriction was an added in case there's a client on the same tier as the WS (which wouldn't be my choice, but have to work with the customer's network architecture..) The client is a hardware device that doesn't support native IIS authentication types (basic, digest, WIA, etc.).
I think I'll recommend enforcing clients in the client tier only, and firewall based IP address restrictions, and see if they can accomodate that. I think their consultants are a bit out of their depth and trying to appear savvy by imposing lots of poorly thought out security prohibitions.
Thanks for the advice!