For some geeks: how to use two internet connections

[bigtiger]

Somebody might know this.

I have two internet connections. One is low speed but has static ip. The other is wireless connection, without public ip but high speed.

Does anybody know how to configure Windows XP so that some application should use the low speed while other applications can use the high speed connection?

Thanks.

Edit: many read, but no answers. I assume most people know nothing about this. But come one, those who know SOMETHING, please put it here. Maybe we can go from there.

[stephenaron]

Good question.

[jdhurst]

I would say: Probably not. Why? Because your system can only use one internet connection at a time (normally configured) and Windows will use the active connection at the time (because all your connections today, slow or fast, use TCP/IP). I have deliberately tried dialing one of suppliers while being on broadband with the other. The dial-up works of course. But Windows gets confused (so also does Linux for those who know no better than to flame). ... JD Hurst

[bigtiger]

Thanks, JD Hurst. It looks like a no-no to me too.

I actually need to use the dial up when I need to use the school library system because it only accepts the IP from dialup. For normal use, I use commercial broandband.

[Wiz]

Windows have a routing table (type "route print" in dos) where the IP adresses on the internet usually follow the default gateway (Dest 0.0.0.0 and mask 0.0.0.0). The default gateway is where all traffic is sent unless there is another more specific route. When you got two interfaces with a link you normally would have two default gateways, but since the traffic have to be sent out one of the interfaces only there is also a metric that decide which one of them to use.

What you could do is to add a route manually. Lets say that you want a default route out the fast speed internet connection (to send all traffic out that interface), but the traffic to 10.20.30.0 255.255.255.0 should be sent out the other interface. Then you could add the command below:

"route -p add 10.20.30.0 mask 255.255.255.0 x.x.x.x" (where x.x.x.x is the correct default gateway for your slow speed internet connection. The "-p" make sure the route is not deleted after a reboot. "route delete.....etc" is to delete the route again. The subnet 10.20.30.0 is just an example is not a valid address on the internet. And then make sure that the default route "0.0.0.0 0.0.0.0" points out the fast speed internet connection. You can change your network connection (change in the windows gui) to specify a metric for that interface instead of using automatic that you would normally do when using DHCP. That way you can make sure the default gateway for one of the interfaces is preferred when there is a link on two interfaces simultaneously. Doing this would make all traffic except the route you specified to be routed out interface 1 and the route you specified to be routed out interface 2.

This solution would make all traffic to some destination addresses to be routed according to the route you add and would be the case for all your applications. So it does not differ based on what application you use. If you want traffic to that destination somtimes to be routed out interface 1 and other times out interface 2 it won't solve your problem.

This would work and i have done it sometimes to be able to use two interfaces at the same time. The route used by windows is based on the destionation address you want to reach though and not what application you use.

Maybe this could be a solution? I hope i managed to explain this so it's possible to understand. I have never tried this with one physical interface and one dialup interface though. In my case i used two physical interfaces on my computer, but you also have the option to chose (for your dialup connection) to not use the default gateway of the remote host.

[bigtiger]

Thanks. Sounds like a solution. I will play with it tonight and get back to you.

[bigtiger]

Just tried. It works pretty good. The only drawback is that I can specify applications. Ideally, I wish I could use IE to use the dialup and firefox to use the brandband.

I will go this route for search for a possible solution.

Thank you very much, wiz.

[seeplus]

You could set up a proxy (like privoxy: http://www.privoxy.org/)

After install, configure it to use one of the connections, and configure one of your browsers to look to privoxy for access. (let the other continue to use the default connection.)

[smugiri]

Just tried. It works pretty good. The only drawback is that I can specify applications. Ideally, I wish I could use IE to use the dialup and firefox to use the brandband.

I will go this route for search for a possible solution.

Thank you very much, wiz.

You can do this to some extent using the Options for Firefox and IE since they are browsers.

In Firefox, choose
Tools->Options

Pick the last tab and click on the general connection button. Under each protocol, type the address of the internet connection gateway that you want to use for that app.

Do the same for IE

Tools->Internet Options

Connections Tab

Lan Settings

enter IPs for each protocol in the box that comes up.