Host underscores

posted on: Wednesday, August 24, 2011 by: jhildeman

Apparently, RFC 592 (I just need to read more) states that we are not allowed to use underscores (_) in "host names" (what IIS calls host headers, others call host names, not the same as domain name rules).  In this case, our WMI scripting allowed us to create a site and slap a host header on it that contained an underscore.  This is where the issue began. 

RFC 592 states…

1. A "name" (Net, Host, Gateway, or Domain name) is a text string up to 24 characters drawn from the alphabet (A-Z), digits (0-9), minus sign (-), and period (.).  Note that periods are only allowed when they serve to delimit components of "domain style names".

Bottom Line:  Apparently IE expects standards to be obeyed (imagine that) and does not allow this invalid "host name" to be written into a cookie (Cookie:  Thus, SiteManager says we successfully logged in (according to the database logs) but because the cookie never got dropped (even when  I put it in "allowed sites" and lowered my security).  Result: we get bounced right back to the login page as if nothing happened (but ONLY IN IE). 

If you change the name of host to "" then everything is fine.

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