2 LAN card Problem

[hisam]

My PC has 2 lan cards:
LAN A - used for local network setup
LAN B - used for broadband internet.

proxy is configured to provide internet to all users over network.
now my problem is LAN B stops working if LAN A is working. if i disable LAN A, LAN B strarts working but i want both to work.

LAN A has 172 series IP (DHCP)
LAN B has 192 series IP (STATIC)

I hope i've made it clear.
Kindly advice

 

[hisam]

i failed to mention that i'm working on WinXP SP3

 

[xehqter]

Possible Answers:
1. Somethings wrong with your proxy software or proxy configuration on the local computer.
2. Your routing tables are incorrect

Questions:
1. Are we talking about Internet Connection Sharing (ICS)?
2. Is the computer in question setup to access the internet directly or through the proxy software and the proxy server accesses the internet?
3. Your using the computer as a proxy server (ie: content filtering on the internal lan) not as a router (providing internet to all the local computers)

 

[hisam]

Your Answers:
1. Nothing is wrong with proxy software.
2. Yes the routing table may have problem...coz to run both LAN currently i manually set the routing table for default gateway..but this is not the solution as i have to do it everytime the system restarts.

Your Questions:
1. No
2. Internet is directly working on this computer.
3. Yes this computer is also working as a proxy server.