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is there any basic proxy server software for Windows that allows you to setup a proxy server on one network interface (NIC/Adapter, etc) and have it route traffic through to the other network interface as if it's being sent from the second interface?

Example: NIC1 tries to send traffic to via a software based proxy server on Software proxy sends the traffic out to through NIC2.


I go to Starbucks a lot, and I like to use their free wifi. However, I would prefer to send specific types of traffic over my tethered phone's 3G connection instead of over the Starbucks network.

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The two Titans have spoken already, but yes, it's technically possible... we're just not sure why you'd want to do that. – gravyface Oct 20 '10 at 20:03
Hi Gravy, see my response to Chopper's answer for more info. – user57735 Oct 20 '10 at 20:22

You could do what you're trying to do with Squid Cache and the tcp_outgoing_address configuration parameter (which I've used on Windows and works fine) but, as Chopper3 says, it's probably better for you to explain why you're trying to do that instead of just asking for what you want to do.


You could use ACLs in Squid to define the particular list of sites that need to be sent out the other tcp_outgoing_address. This is a bit of a heavyweight solution for your own local machine but it's certainly feasible to do.

This isn't necessarily a Server Fault-type question, but it's possible that somebody could want to do something similar in a corporate LAN setting.

I've got a Customer site where, for example, accesses to some web sites through a proxy server need to be stamped with a "special" source IP address (by way of the tcp_outgoing_address directive an an authentication ACL that back-ends to the Active Directory) depending on how the authentication occurs (to allow a rather "dumb" upstream proxy server to know that the user is of a given "class" designation when accessing these web sites).

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Hi Evan, thanks for your response, see my comments below Chopper's response. – user57735 Oct 20 '10 at 20:22

I'd sooner hear what you're actually trying to achieve here as what you're describing either makes little sense, is a router or is a simple matter of defining static routes. Can you come back with much more detail please.

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hi Chopper, I can elaborate a little more. I go to Starbucks a lot, and I like to use their free wifi. However, I would prefer to send specific types of traffic over my tethered phone's 3G connection instead of over the Starbucks network. Ideally, I could create a local proxy so that I can use a web browser for whatever traffic I want to send over my phone and another browser for Starbucks-bound traffic. – user57735 Oct 20 '10 at 20:20
Ah ok, well firstly this isn't the best forum for this kind of question, that would be our sister site, secondly this is easier to do via static routes. – Chopper3 Oct 20 '10 at 20:27
I don't know if static routes would be easier or would work for that matter, maybe policy-based routing, but it all depends on what he means by "types of traffic". – gravyface Oct 20 '10 at 20:33
Thanks :) Sorry for posting on the wrong forum :P – user57735 Oct 20 '10 at 20:42

Like Evan suggested, setup Squid on your Windows machine using the tcp_outgoing_address to direct localhost traffic out through the 3G network interface.

To control what sites going out through Squid**, you could use something like FoxyProxy, a FireFox add-on, that allows you to configure your proxy settings on a per-domain/URL basis, so that when you want to direct traffic to a certain domain or URL out through your 3G connection, you'd add it to the list in FoxyProxy's settings.

** there may be a method of pairing the tcp_outgoing_address with a URL whitelist directive in Squid, but I'm not certain.

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