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IIS and multiple IPs

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So it was that we had a site that was needing to pull in some XML data from a clients internal system. Not a huge deal, we do it all the time. The client needed to restrict the data to an IP address for security. Also not a problem, we do that quite regularly. But as it turned out, it was a problem. A small, annoying problem that the client caught onto.

You see, in an IIS server that has multiple IPs going to it, you can assign an IP to a site. This is what we did here; specifically set the site to respond to a certain IP. The client allowed an exception to that IP. But it still would pull in data.

Begin frustration.

After more than a day of fiddling around with setting, I asked the client to pull up the IP of the site we are working on. They did, and confirmed that the site was from that IP. But there was also something else. Another IP entry in their firewall logs. Turns out, that was one of our IPs.

Weird. So I asked the client to add exceptions to all the IPs running to our server. He did. And low and behold, the site is pulling in the data now.

Begin confusion.

The data grab is being done on the backend through an XML load. Apparently, the server decided to use whatever available channel to grab the data. In this instance, it was the first IP on the list. So it turns out that the IP we specifically set the site to respond to is just that, it responds to just that IP, and responds only. Getting data, however, is a different matter it seems, ad the site will use whatever available IP, regardless of what the site is set to respond to.

End confusion. End frustration.

I havent seen where to set IIS to only pipe data trough the IP we assign it, but at this point I am not really concerned about that. It works and for now, I will take that as a win.

So in the future, if you use IIS, be sure to allow exceptions for all IPs to the box when needing to get data from an external source. Save yourself the frustration. Then go have a beer.

Mmmm, beer. :)

Written by iGonzo

July 19th, 2011 at 12:42 pm

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