Your event log contains a warning similar to:
I had just set up a new .NET domain controller and allowed it to install DNS, and NAT and the firewall to provide internet access for my clients via the server's DSL Adapter.
I was a little worried, until I realized that the reverse-lookup zone had NOT been configured.
Since the server has an IP address of 192.168.0.1, I used DNS Manager to configure a reverse-lookup zone with 192.in-addr.arpa, which solved the problem.
NOTE: Unless you manually open some ports, the firewall prevents access to your server from the Internet.