Domain Names have a variety of basic rules, in general domains must: 

  • Use only letters, numbers, or hyphen ("-"). 
  • Cannot begin or end with a hyphen. - .com, .net, .org and .info domain names cannot exceed 67 characters total. 
  • .info and .biz must have at least 3 characters not including .info or .biz. 
  • Other domain names cannot exceed 22 characters, not including the extension. 
  • Domain names are not case sensitive. 
  • Domain names cannot include spaces. 
  • 2 letter domains are not permitted. Strictly speaking domain shouldn't begin with a number either, however in practice it is possible in most circumstances.