URL Rewrite + SharePoint = No Support


imageUsing ISA, IAG, TMG, custom code or the URL Rewrite Module to modify the path of your SharePoint 2007 URL’s? Word on the street, read twitter and from other new friends, is that you are running an unsupported SharePoint Deployment. You may be asked to remove the rewrite before Microsoft Product Support will help you. This is for 2007, the answer on 2010 may not be definite yet, but I would recommend thinking twice before implementing there, as well.

Counter Example

imageWhat about CKS:EBE? Obviously, I’m a fan. I wouldn’t publish to a public SharePoint blog without it. The SEO benefits are enough for me to risk the supportability. Plus, I’m not the admin on this box. :;
Seriously though, this blog, running Enhanced Blog Edition had the number one hit for SharePoint 2010 for 6 months after that was announced as the official product name. Currently, #3 on bing for sharepoint bing maps That’s some serious Google and Bing karma!
Grain of salt: This is custom code that may not be seen as easily removed. Even though you can configure CKS:EBE to not use the rewriting the code still exists in the assembly deployed to the farm.

Official Microsoft Statement

imageThe official word on modifying the path of a SharePoint URL was pointed out to me by a friend, thanks Maurice. Read TechNet Article CC288609 and pay close attention to the following:
Some reverse proxy devices can modify the path of a request (the portion of the URL that comes after the hostname and port number) in such a way that a request sent by the user to http://www.contoso.com/sharepoint/default.aspx, for example, is forwarded to the Web server as http://sharepoint.perimeter.example.com/default.aspx.

This is referred to as an asymmetrical path. Windows SharePoint Services 3.0 does not support asymmetrical paths. The path of the URL must be symmetrical between the public URL and the internal URL. In the preceding example, this means that the “/sharepoint/default.aspx” portion of the URL must not be modified by the reverse proxy device.

If you find that Note confusing, you are not alone. I didn’t get the “you are not supported” vibe from that the first 10 times I read it. My skull is thick, but Spence has a big hammer! 🙂

Redirect all you want, rewrite with care!

The twitter conversation, from the reply side follows. Note MCM Brian Porter’s comment about redirection. This has been echoed by other experts in the field.

Doesn’t a mugs game sounds fun? Love that British English! 🙂


  1. I’m a PFE @ Microsoft and have had my customers call Microsoft Support in the past and they have asked them to remove the rewrites before offering them support. Re-writing is extremely useful; I’ve heard that 2010 may offer some re-writing capability out of the box, much like blogs such a WordPress do. It would be nice, but haven’t seen anything to date that confirms it.

  2. Thanks for the feedback, Jason. Always good to have input from Microsoft Field Engineers on these kinds of issues. It’s useful and in some cases, it works, but I understand how it get’s in the way of troubleshooting.

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