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My CDN server is getting blocked on certain corporate networks. I have added my CDN site to most corporate firewall directory to make sure its categorized correctly and not as a parked domain or other categories which are considered spam by web filtering softwares used by corporates. I guess the reason is that my CDN domain name is not the same as my websites domain name. Why I did this? Because I wanted to use a cookie-less domain for all my static stuff (images/css/js) like everyone else (twitter, youtube). Is there a place which lists all such directories where I can categorize my CDN domain? Is this the best way to do this? I guess the ROI of this optimization is pretty low and I might consider moving my CDN domain as a sub-domain of my website domain if I dont get any convincing answer to this.

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up vote 1 down vote accepted

Putting your assets in a separate domain is a common practice, even Server Fault does it ( I doubt any of your hypotheses are correct, because they would cause problems with too many other legitimate sites. I would contact some of the corporate networks that you're being blocked by (or have the users at those sites do it) and find out why you're being blocked.

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Thanks for your answer. I did check with one network where it was blocked. And the network admin told me my CDN domain was categorized as a parked domain in his web filtering software, which was the reason why it was being blocked. Also found that the other reason could be that the root (/) of such a domain should not serve any page and should rather throw 403. – user32182 Jan 19 '10 at 8:56
So ask them how they determine a domain is parked, and fix that. – womble Jan 19 '10 at 9:07
Yes I have done that already (in this case I needed to list my domain in their directory under the relevant category - the reason was that i needed to send 403 on the root of my webserver). However cant do that for all such software available in the market. So what I wanted to know was the set of rules which is like a super-set of all such rules used by all sch software. – user32182 Jan 19 '10 at 9:31
There is no such list; proprietary block lists are always dreaming up new ways to screw their customers. You'll just need to play whack-a-mole and fix things as you find out about them. – womble Jan 19 '10 at 23:41
Yeah, I guess thats what I need to do. Worst case can make my CDN domain a sub-domain of the website domain. Thanks for your help. – user32182 Jan 20 '10 at 6:51

The ip range for google app engine is being blocked by web trends. I don't think there is anything you can do if you are using google app engine besides setting up a small js script to detect if the CDN is being blocked, and in which case using your local resource files instead.

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I think there is no other option but what you suggested. A javascript which could detect this and load from your alternate CDN. – user32182 Feb 1 '10 at 15:47

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