Configuration settings for the TCP/IP protocol are stored in several Registry keys. You can find some of these settings in the following branch:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services
This branch contains the keys
\VXD\MSTCP,\VXD\MSTCP\ServiceProvider,\VXD\MSTCP\NodeType, and \Class\NetTrans\000x, all of which contain multiple TCP/IP settings.