I have a Win2k server used as an ATM switch with dual NICs. The premise is that my server will receive an ATM request from an ATM service provider using a frame relay through NIC 1. Then I switch that request, using proprietary software, through the second NIC to the Internet to my clients database server. Their server reply returns the same way through my second NIC and the its switched to NIC 1 back through the frame relay.
NIC 1 - Uses frame relay circuit to ATM Service Provider. Does not touch the Internet
IP address - 18.104.22.168
Subnet Mask - 255.255.255.0
Gateway - 22.214.171.124
No DNS addresses
Persistent route - 126.96.36.199 mask 255.255.255.255 188.8.131.52
NIC 2 - Private IP behind my firewall and accesses the Internet
IP address - 184.108.40.206
Subnet mask - 255.255.255.0
Gateway - 220.127.116.11 (Firewall)
DNS addresses configured for Internet access
This system worked great till my ATM provider changed their IP on the far side of the Frame relay circuit. All I did was change the Route Add to point to the new static IP using the same class C public IP on my NIC 1.
Persistent route - 18.104.22.168 mask 255.255.255.255 22.214.171.124
Now I cannot ping or access the Internet with NIC 2. The pings get lost and never reach my firewall router. It seems that the static route I added with the Route Add command redirects the pings from NIC 2 to the frame relay circuit and then go to bit heaven. If I delete the static route through the command prompt then NIC 2 will ping and access the Internet successfully. Then I re-add the static route and all is golden till the Server needs to be rebooted and it starts all over again. I have worked around this by writing a small batch file that deletes the static route, pings an Internet address and then adds the static route back. Funny thing is I have another server setup the same way using another ATM service provider and it works great.
BTW, I have replaced the NICs and cabling and have disable IP routing on the server. I also added another static route pointing my private IP to the WAN side of my firewall in hopes of telling it where to go to access the Internet.