Why won’t asp.net create cookies in localhost?

The cookie specs require two names and a dot between, so your cookiedomain cannot be “localhost”. Here’s how I solved it:

1. Add this to your %WINDIR%\System32\drivers\etc\hosts file:
   127.0.0.1 dev.livesite.com

2. When developing you use http://dev.livesite.com instead of http://localhost

3. Use “.livesite.com” as cookiedomain (with a dot in the beginning) when creating the cookie.
   Modern browsers doesn’t require a leading dot anymore, but you may want to use anyway for backwards compability.

4. Now it works on all sites:

   • http://dev.livesite.com
   • http://www.livesite.com
   • http://livesite.com