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We have a product that uses Web Services. On our primary testing here on our local site, the product seems to be functioning well. When the product was deployed on another site, it went crazy with the infamous ISA HTTP 407 error.

So I have a couple of questions regarding ISA:

  1. How do you know if a network is ISA enabled?
  2. Can a Windows Machine be affected by the ISA server even if it is not joined to a domain?
  3. Since the web service is on the SAME MACHINE as the product, is there a way to tell the machine to not process the HTTP traffic through the ISA Server?


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Which version of ISA? And what do you exactly mean by "ISA enabled network"?!? – Massimo Feb 15 '10 at 9:55
up vote 1 down vote accepted

ISA Server is a firewall/proxy, so it can only affect external connections, and only if it's your gateway and/or if you use it as a proxy; it should definitely not affect connections from one machine to itself.

Have a look at the proxy settings in Internet Explorer; is your ISA server configured there? If yes, try disabling it or adding an exclusion for localhost,, your computer's host name and/or its IP address.

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Is it possible that a machine will use the ISA server even if the proxy setting in IE is blank? – Ian Feb 15 '10 at 10:37
For Internet connections, yes: ISA will always act as a web proxy when you use it as a gateway, even if you don't explicitly configure IE to use it. For local connections, this could only happen if you have the ISA Firewall Client installed, which hijacks the whole Windows networking stack in order to forward everything through ISA; but it shouldn't anyway affect loopback connections. – Massimo Feb 15 '10 at 11:10
By use it as a gateway, do you mean the gateway in the NIC properties? – Ian Feb 15 '10 at 11:39
Yes. I mean having ISA as your gateway/firewall to the Internet. – Massimo Feb 15 '10 at 12:01
Solved our problem by detaching the machine to the network. – Ian Feb 16 '10 at 6:22

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