i have the following scenario.

Two laptops are connected via a router through the Ethernet ports. These two computers need to be able to communicate together. One computer also needs to access the internet through a different adapter (i.e. we will taking these two laptops two various sites where by the most common type of internet access will be wireless).In isolation all of the various adapters work fine (i.e. the internal network works fine, and the wireless connects to the internet). However,we try to turn on all of the adapters at the same time,the following occurs:

  • If we bridge the two network connections together on the "Server" -The internet connection doesn't work through the wireless
  • If we don't bridge the connections
    • The internet connections don't work

It seems like http traffic is trying to be sent through the Ethernet adapter (which of course is not connected to an internet connection).

How can we solve this?

  • What networks are you using on the different adaptors? – Jason Tan May 10 '10 at 13:50

I suspect you need to put both laptops on one network, e.g. this must be a different network to what the internet connection is provided through.

Then put the internet connected laptop on it's network, which I assume will be defined by the internet connection. Let's assume its

Then you need to set the default route on the internet connected laptop to use the internet network's gateway. I.e. the internet connected laptop will need to use as it's default route.

You can do this with the route command, though I am not familiar with the windows version of it, I know it exists and I am pretty sure you can jigger the routing table with it.

Be aware that this will not allow the non internet connected laptop to get out onto the internet, but from how I read your question, that is not a requirement.


You haven't said what O/S you're using, but what you need is the equivalent of "internet connection sharing", which certainly used to be present in MS operating systems, and is also available on OSX.

Turn this on on the system which has dual connections, and then it will act like a DHCP server and NATing router for the second system. That second system should be connected to the first with an ethernet switch or if there's no other device just a crossover cable - no router required.

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