\chapter{DNS}

\begin{quote}
    Domain Name Servers (DNS) are the Internet's equivalent of a phone book. They maintain a directory of domain names and translate them to Internet Protocol (IP) addresses.
    
    This is necessary because, although domain names are easy for people to remember, computers or machines, access websites based on IP addresses. 
\end{quote}\footnote{\href{http://www.networksolutions.com/support/what-is-a-domain-name-server-dns-and-how-does-it-work/}{networksolutions.com/support/what-is-a-domain-name-server-dns-and-how-does-it-work/}}

\pagebreak

\section{Hierarchy}

\wikicommonspublicdomain{Domain_name_space}

\pagebreak

Is hierarchical by design going from:

\begin{enumerate}
    \item the root zone at the top of the pyramid,
    \item to the \gls{tld} zones\footnote{Fx. \gls{cctld}/\gls{gtld} zones: .org, .net, .uk, .au, .mil, .aero},
    \item to the sub-zones\footnote{Fx. .co.uk, .org.uk, .net.au, .co.cc} a level below.
\end{enumerate}

\wikicommonspublicdomain{Example_of_an_iterative_DNS_resolver}

\pagebreak

\section{Record Types}

\begin{itemize}
    \item \itemhead{A} Stores info on \gls{ip4} address.
    \item \itemhead{AAAA} Store info on \gls{ip6} address.
    \item \itemhead{CNAME} Store URL pointing to another URL (a.k.a. \gls{a}/\gls{aaaa} records).
    \item \itemhead{HINFO}
    \item \itemhead{ISDN}
    \item \itemhead{MX}
    \item \itemhead{NS}
    \item \itemhead{PTR}
    \item \itemhead{SOA}
    \item \itemhead{TXT}
    \item \itemhead{DNSKEY}   
\end{itemize}

\section{DNSSEC}

\subsection[KSK]{Key Signing Key}

The \gls{ksk} is a used to sign other keys. Thus creating a chain-of-trust.

A prime example of this the current \gls{dnssec} infrastructure on the internet. Where \gls{icann} is controlling and managing the Root zone \gls{ksk} used today. And for the first time in history will do a \gls{ksk} rollover in the fall of 2017.\footnote{The 1st key was issued in 2010.}

The \gls{ksk} is used to sign the DNS root-zone. All the TLD zones then have their own key called a \gls{zsk} used to sign all the domains requesting a key to sign their domain. The \gls{zsk} is signed by the root-zone \gls{ksk}.

\subsection[Rollover]{KSK-Rollover}

