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Category : Windows

Localhost unavailable on Windows

I recently fixed an issue that had been plaguing one of my development machines. The issue appeared after installing a service pack for Windows 2008. The range of symptoms was quite wide so it took me a while to realized that they were all linked to the same configuration problem.

  • “Localhost not available” when browsing to local applications hosted on IIS
  • Visual Studio development web server (cassini) could not be accessed. This was forcing me to use IIS for web development.
  • VMM 2008 (Virtual Machine Manager 2008) was really slow and some functionality was unavailable
  • Inability to upgrade from VMM 2008 to VMM 2008 R2
  • WinRM did not function

All these issues were caused by the same configuration error in the hosts / lmhosts file. This file is located in C:\Windows\System32\drivers\etc. The file contained no IP v.4 entry for localhost at 127.0.0.1 but had an IP v.6 entry for localhost. The solution is simple, either add an entry for IP v.4 or comment the entry for IP v.6. Either way, your file should like this

127.0.0.1       localhost
::1             localhost