Windows xp dual-nic NAT awareness

Solution to a Single Windows XP dual-nic NAT problem --

 

Windows XP, dual network card, one connected to the internet, the other connected to the Intranet, do not work! Finally, I found out the crux of the problem... a concept: the number of hops.

The number of hops indicates the routing overhead, usually the number of hops to the IP target location. Everything on the local subnet is a hop, and every router that passes through it is another hop. If multiple routes have different hops to the same targetSelect the route with the lowest number of hops.

 

Environment:

Windows XP sp2

Internet connection: 10 M [binding IP addresses to MAC addresses]

LAN connection: 100 M

Problem: After the M internal network card is enabled, you cannot access the Internet. Disable it! This problem causes NAT failure.

[1] initially suspected route problems, route print has

Active Routes:
Network Destination Netmask Gateway Interface Metric
0.0.0.0 0.0.0.0 202.118.125.1 192.168.1.220
0.0.0.0 0.0.0.0 202.118.125.1 202.118.125.3630

Problem detected: the number of external network hops is greater than the number of Intranet hops.

Solution: modify the number of Intranet and Internet hops. After modification, the route print includes:

Active Routes:
Network Destination Netmask Gateway Interface Metric
0.0.0.0 0.0.0.0 202.118.125.1 192.168.1.230
0.0.0.0 0.0.0.0 202.118.125.1 202.118.125.3620

Local Internet access and NAT are normal.

The actual process took several hours.