DNS Server Safety | Main Purpose of DNS | DNS type and Layer.

DNS Server

Main Purpose of DNS.
       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.
Safest DNS Server.
      Google Public DNS. IP Addresses: 8.8.8.8 and 8.8.4.4.
                     OpenDNS. IP Addresses: 208.67.220.220 and 208.67.222.222.
                   DNS Watch. IP Addresses: 84.200.69.80 and 84.200.70.40.
OpenNIC.
UncensoredDNS

DNS Layer.

       In OSI stack terms, DNS runs in parallel to HTTP in the Application Layer (layer 7). DNS is in effect an application that is invoked to help out the HTTP application, and therefore does not sit "below" HTTP in the OSI stack. DNS itself also makes use of UDP and more rarely TCP, both of which in turn use IP.

DNS and its Type.

      The most common types of records stored in the DNS database are for Start of Authority (SOA), IP addresses (A and AAAA), SMTP mail exchangers (MX), name servers (NS), pointers for reverse DNS lookups (PTR), and domain name aliases (CNAME).

DNS Hacked.

      Malware attacks can infect your router, and change its DNS settings so that it uses hacker-owned DNS servers instead of legit ones.

One of the best examples of this was the DNS Changer malware. It changed router DNS settings to force online users to visit websites where cyber criminals displayed dozens of ads.

DNS Hijacking.

      DNS hijacking is a process in which an individual redirects queries to a DNS (Domain Name System). It may be accomplished through the use of malicious software or unauthorized modification of a server. They may also direct users to pages containing malware or a third-party search engine.