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Windows 7: Problem with 2 NIC catds in WIndows 7

09 Dec 2011   #1

windows 7 64 bit
Problem with 2 NIC catds in WIndows 7

I have WINDOWS 7 PC with a built in NIC card. I have added one more NIC card(PCI card).
One NIC card I use for Public network(Local intranet with static IP say through which I access Internet.
The other NIC card I use for Private Network where I will connect my device(static IP Just connected to one device).
When both the NIC cards are enabled My internet(first card) works fine I could able to access internet but when I connect my device
it doesnt get the IP address(I run DHCP in my PC).
If I disable my first NIC card(Public network) ,
My device gets the IP, I mean second NIC works fine if I disable the other one.

Please help me to resolve this.

My System SpecsSystem Spec
29 Dec 2011   #2


if your device has a name, have you put that name in your hosts file if it is not on DNS or any kind of nameservice?
have you configured the gateway and netmask properly for your private network? if you are using a router, the gateway should be or .2.1 or .0.1 depending upon your router's address.
netmask will probably be
NIC's IP should probably be
don't know what you are going to use for DNS servers on your private network...
My System SpecsSystem Spec
02 Jan 2012   #3

windows 7 64 bit

My device doesnt have a name. I have not added any entries to the 'hosts" file.
In Windows XP , 2 NIC cards used to work fine. But after I upgraded to Windowz 7 , if my public NIC card is enabled my device on private network doesnt get IP( i run DHCP server in my machine). If I disable the public NIC my device on private network(device directly connected to the NIC through ethernet cable) , it works fine.

If i configure the gateway in host file will it work?

I will try and update you. Thaks for the reply.
My System SpecsSystem Spec

03 Jan 2012   #4


if you are using DHCP you don't have to worry about a thing.
but if a static IP, the gateways on the NICs must be set correctly to the routers that they are supposed to be assigned to. also, the DNS servers should be set to the appropriate nameservers, or you will not be able to resolve domain names.

there is a question of whether TCP/IP can actually figure out which connection to go through though... I suppose you could set up a routing table with a batch file or something if need be, but I am not skilled in that.
I just know that to print the route tables you do from a cmd shell
route print
route /?  (this is help)
I personally have had nothing but trouble using 2 network adapters simultaneously. so I usually end up disabling one and enabling the other to keep things from doing 30-minute timeouts where it hangs the machine (but this is XP I am talking about, maybe 7 is different - probably still don't have such a thing as a "default" network adapter yet).
My System SpecsSystem Spec
03 Jan 2012   #5


don't follow that advice, yet, I have some answers coming...
My System SpecsSystem Spec
03 Jan 2012   #6

win7ult64sp1retail Multi-NIC, Multi-Network Internet Connection Sharing: Pros, Cons - why to avoid
How to Use Two NIC Cards in One Computer | 2 NICs,1 computer (bridging,ICS (avoid ICS,can't disable)
How to Bridge a Wired NIC With a Wireless NIC | bridge wired,wifi NICs
How to Set Up a Server to Use Two NIC Cards | How to Set Up a Server to Use Two NIC Cards
How to Use Multiple NICs in Windows | windows 7+ multiple NICs
one computer, 2 NICS to 2 networks 1 computer 2 NICs 2 networks (XP) READ even if no XP!

I googled "2 nics in one computer". the 1st 2 articles haven't been posted yet, I have one more article I am writing.
My System SpecsSystem Spec
16 May 2012   #7

windows 7 64 bit

I was living with this problem since I was busy. Thank you very much for your post. I will try your suggestion and keep you updated.
My System SpecsSystem Spec
16 May 2012   #8

windows 7 64 bit

Hi jmichae3,

I am not trying for Internet connection sharing. I have 2 NIC cards , one for Internet and other one private where i connect my device . I run a DHCP server on my machine , to assign IP to my device on the second port. When the first port is (Internet) disabled , the second port assigns IP to my device. But if first port is enabled , DHCP does not asign IP to my device . This is my problem.
My System SpecsSystem Spec
16 May 2012   #9

Windows 7 Ult, Windows 8.1 Pro,

For Windows 7 the link below explains how to do this but you aren't really using both NICs for an internet connection, you are connecting with one and sharing the connection from the other NIC. In other words if you already have a router why do this.

Even if you have both a wired and wireless NIC enabled and connected to the internet Windows will tend to choose the wired connection only.

In general Windows 7 won't allow you to be online with both NICs at the same time.

It is not recommended for the average computer user to use either of these methods to share an Internet connection. You are usually better off with configuring a router to work side-by-side with your modem. The reason for the suggestion against using two NICs is because both methods require your computer to be on for others to connect to the Internet. You should only do this if you plan to keep the computer on continuously or do not mind preventing the other computers in your network from accessing the Internet while the main computer is off. The more computers you have connected to an unsecured network, the more vulnerabilities you are exposing. You should always have a hardware or software firewall running on your computer aside from the basic operating system firewall. The most recommended type of firewall is one that prevents Denial of Service (DoS) attacks and port scans against your computer. Hackers can easily infiltrate networks that are not behind an NAT (Network Address Translation) service.
My System SpecsSystem Spec

 Problem with 2 NIC catds in WIndows 7

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