IIS 8 Random 503 service unavailable

There is nothing picking up the phone...

IIS is defaulting all the way to checking if directory browsing is turned on. This implies ASP.net is not getting the request at all.

Make sure there is virtual directory setup where folder looks different that regular folders.

Unfortunately I don't do IIS 7.5, still IIS 6.0.

In 6.0 I would right clikc the folder and click Create App. and then goto the last tab and make ure ASP.net was confgured on the folder.

The last possbility is that the ASP.Net routing engine on root is sucking up all the requests for the sub.

you should really fix the problem, but you could run something like this for a temp solution:

#!/bin/sh                                                                                                            
HTTP_STATUS=`lynx -head -source http://mysite.com |head -1 |awk '{print $2}'`                             
if [ "$HTTP_STATUS" = "503" ]                                                                                       
then                                                                                                                 
        /etc/init.d/http restart                                                                                   
fi