Vamos tentar os mais fáceis primeiro:
(No Internet Explorer; e suponho que você esteja usando o IE porque está executando o IIS no 127.0.0.1 e faz referência ao arquivo hosts em \ drivers \ etc.)
1.) Navigate to "tools", "internet options", "connections", "LAN Settings".
2.) Make sure, "Bypass proxy server for all local addresses" is selected.
Agora, hmm. Supondo que você esteja executando um servidor DNS interno / endereços IP privados:
3.) In a command-prompt, run: "ipconfig /registerdns"
4.) Ensure that you can forward and reverse ping your machinename w/ it's internal IP address.
5.) If "localhost" isn't working, try pinging localhost at the command prompt, it's resolving to 127.0.0.1, yeah?
Vamos limpar esse arquivo de hosts:
5.) Make sure your hosts file wasn't inadvertently saved with a ".txt" extention. If so, remove it.
6.) In your LAN/adapter settings, make sure that you don't have any DNS suffixes to be appended.
Curioso para ver se algum deles resolveu o problema.