Client can't access the internet via NAT

Case Study – Client can’t access the Internet through Windows NAT

Situation: The client just installs a Windows Server 2003 as a NAT server. The server comes with 2 NICs, one connecting to the DSL line for the Internet access and another one connecting to the LAN. All clients and server can ping each other. The server can access the Internet.

Problem: No client can access the Internet.

Troubleshooting: 1. All client use the server inside IP as default gateway and can ping the IP.

2. The client can’t ping the outside IP and any public IP like 4.2.2.1.

3. The tracert displays the accessing internet stop in get inside IP and never get to the outside IP.

4. The result of ipconfig /all on the server shows that both NICs’ default gateways point to the DSL modem.

Resolution: in a multihomed server, you should only assign default gateway on the outside NIC and keep the inside NIC gateway blank. The outside default gateway should point to the router. Otherwise, inside computer can't route to the outside.

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