Authentication problems for non localhost

[yofnik]

I have seen this issue posted a number of times, but never a solution.
Can someone please help.

If I access my web application that uses Forms Authentication using
"localhost" (http://localhost/myapp) or by its IP address
(http://192.168.100.1/myapp), authentication works fine. The
authentication cookie gets created, the user is logged in, and can
access the rest of the appliation.

If I try to access the web application using its machine name
(http://machine_name/myapp), Authentication does not work. The cookies
does not get saved and the web application keeps redirecting back to
the login page.

What can be causing this? Does anyone have any advice.

Thanks.

 

[yofnik]

Ok, I think I have finally figured out the problem. Microsoft Security
patch MS01-055 caused any hostname with an underscore "_" to stop
processing cookies properly.

http://support.microsoft.com/default.aspx?scid=kb;en-us;312461

I wish I can charge Microsoft for my lost productivity. The question
now is whether there is a reasonable workaround without having to go
around and rename my servers.