DNS Configuration

A Presentation

On

DNS CONFIGARATION

SUBMITTED BY:

Vinod Gour

CONTENTS:OverviewHistoryDNS-Name Space & WorkingExample of DNS Name SpaceDNS-Name ServerDNS-ZoneDNS-Configuration

DNS-OverviewDomain Name System (DNS) is a database

system that translates a computer's fully qualified domain name into an IP address.

For example Domain name www.amazon.com corresponding to IP address (207.171.166.48).

DNS serves as an electronic telephone book for a computer network.

HISTORY OF DNSIn 1967, DNS did not exist.

in 1971, Peggy Karp conceived of “host mnemonics” (RFC 226) and develop “HOSTS.txt”

The first version of this file was distributed in 1972.

The Domain Name System was conceived in RFC 799 in 1981 Written by Dr. David Mills.

In 1987, the publication of RFC 1034 and RFC 1035 updated the DNS specification.

DNS –Name Space & WorkingThe namespace refers to the hierarchical layout of

DNS names

the DNS namespace is laid out in an inverted tree.

At the top of the DNS namespace is the "Root" defined by null character

The root is not normally explicitly specified in user applications but when specified is denoted by a trailing period(www.vtc.com)

DNS –Name Space & WorkingBelow the root in the DNS namespace, are

the top level domains or TLDs.

These TLDS are maintained by the Internet corporation for assigned names and numbers, or ICAN, for Internet use

On a private network you can use any TLD you want but it is bad practice in case you ever connect your network to the internet.

DNS –Name Space & WorkingThe remainder of the namespace is open

for use

You can register domain names beneath several of the TLDs

An Example of Name-Space

DNS-Name ServerA Server which handles DNS-Queries called “Name-Server”.

This server hold a list of all the IP addresses within its network and a cache of IP addresses.

When your computer requests an IP address, one of three things happens.

DNS-Name ServerIf the requested IP address is registered

locally.

If the requested IP address is not registered locally ,but someone within your organization has recently requested the same IP address.

If the requested IP address is not registered locally, and you are the first person to request information about this system in a certain period of time.

DNS ZONESEvery domain name, which is a part of the

DNS system, has several DNS settings, also known as DNS records. In order for these DNS records to be kept in order, the DNS zone was created.

Their are 2 types of zones:1) A forward lookup zone 2) A reverse lookup zone

DNS ZONESA forward lookup zone is a DNS zone in

which hostname to IP address relations are stored. When a computer requests the IP address of a specific hostname, the forward lookup zone is queried and the result is returned.

A reverse lookup zone does just the opposite. When a computer requests the hostname of an IP address, the reverse lookup zone is queried and the result is returned.

DNS-Co

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STEPSIt involves following steps:-sudo sunano /etc/network/interfaces – for static IP./etc/init.d/networking restartifconfigapt-get install bind9nano /etc/bind/named.conf.localnano /etc/bind/db.up.omg (forward lookup zone)nano /etc/bind/db.192 (reverse lookup zone)nano /etc/resolv.conf/etc/init.d/bind9 restartnslookup sgsits.up.omg & nslookup 192.168.1.3

Step 1 : nano /etc/network/interfaces – for static IP

Step 2 : /etc/init.d/networking restart

Step 3 : ifconfig - Our DNS Server has now a static IP

Bind9BIND (Berkeley Internet Name Domain) is an

implementation of the DNS protocols and provides an openly redistributable reference implementation of the major components of the Domain Name System.

BIND9 is latest version of BIND architecture.

 features of BIND9 : are DNS Security, IPv6,DNS Protocol Enhancements, Views, Multiprocessor Support, and an Improved Portability Architecture.

Step 4 : apt-get install bind9

Step 5 : nano /etc/bind/named.conf.locals

Step 6: nano /etc/bind/db.up.omg

A(Address):points our domain to an ip address.

AAAA: same as A record.

CNAME(Canonical name): this record points our sub-domain to another domain name

MX(Mail exchanger): MX records control where our emails are received.

DNS ZONE RECORDS

PTR(Pointer): defines what name will be called when an IP address is looked up. 

TXT: The TXT records are custom records which contain machine-readable data.

NS: identify the names of the DNS servers.

DNS ZONE RECORDS

Step 6 : nano /etc/bind/db.up.omg

Step 7 : nano /etc/bind/db.192

Step 8 : nano /etc/resolv.conf

Step 9 : /etc/init.d/bind9 restart

Step 11 : nslookup sgsits.up.omg & nslookup 192.168.1.3

THANK-YOU