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At work, I use a laptop.

It is a Dell Latitude D630 with Windows XP.

I work in a lab environment where I need to use the Ethernet Port as a Static IP to interact with a local network (which cannot talk to the outside world).

What I would like to do is use the Wireless as the internet connection so i can check email, etc at the same time I am using the ethernet network... It seems like this is not possible. Is there a piece of software or a way to configure it to allow me to do this?

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unplug from network, connect to wifi check emails, disconnect wifi, plug in network resume work. – ken Apr 29 '11 at 19:14

If you do connect to the wired LAN and the Internet at the same time on the same machine, then your lab LAN will be connected to the Internet, and will be vulnerable to attack through your machine. If there is a reason for keeping the lab LAN separate from the outside world, then don't use your machine to connect to both at the same time. Use a separate machine for each environment.

If you are go ahead and connect to both, XP can do what you ask. All you need to do is connect to the wireless network, then set a route for the lab LAN out the Ethernet device. The default route will point to the wireless device, giving you access to the Internet, and packets to addresses on the lab LAN will go out the Ethernet device. Also, if the lab network is small, you can add the names and addresses of the lab machines to your hosts file so that your machine will be able to address lab LAN machines by name. Get the lab network numbers from the people running the LAN, or just ask them for a route command that configures your machine. If you need help with route, tell us what you need.

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The risk of someone hacking from the Internet into the lab LAN via his machine seems not that large to me. For one thing, the router he used for wireless would be NATed, wouldn't it? This would automatically discard any packet that was not part of a connection originating from his PC. Still, I suppose it could somehow happen. But he should also be able to add a filter to the wireless router to discard inbound packets that had the local LAN as a destination. No? – irrational John Jun 28 '10 at 5:00
@irrational John: That's assuming his machine isn't compromised. If his machine is infected, an attacker could then gain access to the LAN. – Andrew Moore Jun 28 '10 at 5:48
I guess it all depends on just how secure this lab LAN needs to be. What you say is also true I would think of every home network behind a router in use today. If any machine on it is compromised then everything else on the LAN is at least technically at risk. – irrational John Jun 28 '10 at 6:14
Yes, that's correct. One hacked machine behind a firewall means dramatically more exposure to other machines on the same LAN. The hacked box can call out through the NAT router by any number of means, and vector in all sorts of stuff. – Fred Jun 30 '10 at 19:46

It's possible, but it's not your typical Windows IP scenario so you would probably have problems with it unless you perform some additional customization.

What you would need is to add the routing info to allow your TCP/IP to determine which of the two interfaces to use depending on the destination you want to exchange data with.

I'm guessing the most likely scenario would be to add a route that specified using your ethernet port to reach your local LAN. Then add a default route that pointed to your wireless interface so any traffic not destined for the local LAN would take that path.

If your IP on the Wi-Fi interface is obtained via DHCP then perhaps the default route established that way would suffice? Haven't tried this on windows so I'm fuzzy on the specifics of how to best do it.

How complicated is the IP addressing of your local LAN?

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