The Theory of the Dot: How We Surf the Internet Incorrectly

 You may not know this, but we're surfing the Internet incorrectly. That's right, when we go to Google or Cybrary, we type:

www.Cybrary.it or www.google.com , but we're forgetting the most important symbol, the dot (.) at the end of the domain.

 According to http://www.dns-sd.org/trailingdotsindomainnames.html:

"It's a little-known fact, but fully-qualified (unambiguous) DNS domain names have a dot at the end. People running DNS servers usually know this (if you miss the trailing dots out, your DNS configuration is unlikely to work), but the general public usually doesn't. A domain name that doesn't have a dot at the end is not fully-qualified and is potentially ambiguous. This was documented in the DNS specification, RFC 1034, way back in 1987:

 

• Since a complete domain name ends with the root label, this leads to a printed form which ends in a dot. We use this property to distinguish between:
  • A character string which represents a complete domain name (often called "absolute"). For example, "poneria.ISI.EDU."
  • A character string that represents the starting labels of a domain name which is incomplete, and should be completed by local software using knowledge of the local domain (often called "relative"). For example, "poneria" used in the ISI.EDU domain."

 What does this mean or why should we care?Let's say you are at a university or a company, and your company has a secondary domain of cybrary.it. You're on the network and you want to go to the website: example.cybrary.it. All you have to type is "example" in the browser and it will automatically go to example.cybrary.it.Now, let's say we wanted to go to Google. In theory, if we type www.google.com, it will go to:

www.google.com.example.cybrary.it - which is NOT what we want.

You want to tell your browser that you want to use the top-level domain and NOT company or university's subdomain. In order to fix this, we use the dot to represent the root of DNS. In our browser, we type www.google.com. (with a dot).  The dot says the URL you entered is a top-level domain and that there are no relative search domains. So remember, if you want to visit a website that's not being filtered with subdomain, make sure to put a dot at the end! This is a common little "hack" you can use to get around computers that are on a private network. Thanks for reading this! Please post your questions and comments below.