I know that the Windows hosts file maps host names to IP addresses. But there is no mapping for localhost. Instead it has a comment that says this:
# localhost name resolution is handled within DNS itself.
# 127.0.0.1 localhost
I don't understand this. Where is this "DNS" that handles this resolution? Is it a program somewhere in Windows OS? Is it outside of Windows? Does it have a config file? How is this being done?