[eluser]CroNiX[/eluser]
[quote author="ThePaavero" date="1354638715"]Make sure you don't have underscores in a possible subdomain. IE freaks out and won't keep the session going if you do.[/quote]
Actually, in this case, I believe IE is one of the few if not the only browser to follow the RFC on this, as an underscore is an illegal character in a domain name - so it SHOULD be rejected.