This Tip Should Tell you Simply and Exactly What’s is a CNAME.
A CNAME Can Be Defined as a TCP/IP-DNS Alias/Pointer that Forward the Request To This DomainName OR to Another DomainName.
A CNAME Resolve/Map a Domain Name Prefix (Like: www, ftp, forum…) To the Corresponding Canonical Domain Name.
Examples:
www IN CNAME thisdomainname.com
Map the URL www.thisdomainname.com To thisdomainname.com
ftp IN CNAME otherdomainfirst.com
Map the URL ftp.thisdomainname.com To otherdomainfirst.com
forum IN CNAME otherdomainsecond.com
Map the URL forum.thisdomainname.com To otherdomainsecond.com
Howto Install Firefox Nightly on Linux:
Firefox Nightly on Linux Distros