title: What are the valid characters that can show up in a URL host?
body: <p>I'm writing some code that processes URLs, and I want to make sure i'm not leaving some strange case out...</p>
  
  <p>Are there any valid characters for a host other than: A-Z, 0-9, "-" and "."?</p>
  
  <p>(This includes anything that can be in subdomains, etc. Esentially, anything between :// and the first /)</p>
  
  <p>Thanks!</p>