Linux and DNS Server


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Linux and DNS Server

  1. 1. Prabhakar Thota
  2. 2.  Linux  Factors of Linux Implementations  What is Linux  Where is Linux Used  Why Use Linux  Linux vsWindows  Web Server Administration (DNS Server)  UsefulTopics  Why Hackers prefers Linux  Speedup Internet with Google Public DNS  Conclusion
  3. 3.  Why accept lower levels of security and reliability when I can provide higher levels of service to my customers?  I don’t want to be locked into any single operating system, platform, or solution technology. It’s about choices.  Why pay more when you can get the same or better function for less with more flexible licensing?
  4. 4.  Linux is a generic term referring to Unix-like graphical user interface (GUI) based computer operating systems.  A famous open source project  It is Multi-user, Multitasking, Multiprocessor  Free to use, distribute, modify under a compatible licence  A combination of many projects
  5. 5.  People improve it, people adapt it, people fix bugs. And this can happen at a speed that, compared to conventional software development. Open source software Continue..
  6. 6.  As there is a limited access of user to basic files and folders, in Linux network it provide security to user’s privacy.Without disclosing the secured data Linux acts as a efficient server. Linux Provide Security Continue..
  7. 7.  Linux is "virus-free", there are no viruses for Linux in the world Linux is aVirus Free Continue..
  8. 8.  No!  There doesn’t exist any Operating System on this earth that is virus free. However Linux is known to have least number ofViruses, till date, yes even less than UNIX OS. Linux has had about 60-100 viruses listed till date. None of them actively spreading nowadays. A rough estimate of UNIX viruses is between 85 -120 viruses reported till date. Linux is aVirus Free Continue..
  9. 9.  75% of respondents were already using Linux and another 14% were evaluating it  43% of all web sites use Linux servers running the ApacheWeb server
  10. 10.  Costs less  Stable  Reliable  Extremely powerful
  11. 11.  Financial Difference  Technical Difference  Linux upgrades faster than Windows Cost Linux Windows Online downloads Free Not available Retail price, CD $ 50 $ 300
  12. 12. Web Server Administration
  13. 13.  Networking in Linux  Linux applications for servers  What is Domain  What is Host name  Understanding DNS  Key components of DNS  Install and configure DNS in Linux
  14. 14.  Linux is a powerful networking operating system  Ability to work as a client, server, or network device  Proxies, firewalls, routers, bridges, etc.  As with most things, GUI tools available  Similar toTCP/IP configuration in Windows  Default firewall software is iptables or ipchains
  15. 15.  All common Internet services available  Mail, Web, DNS, etc.  Easy administration using web based interface  No cost to setup a server.  As easy as download a CD and install.  Lower maintenance. Keeps running for years.
  16. 16.  Domain Names are the unique name that identifies an entity.  Domain Names always have 2 or more parts separated by the dots.  Types  Top level domain  New –Top level domain
  17. 17.  .edu, .gov, .com, .net, .org, …  Countries each have a top level domain (2 letter domain name).
  18. 18.  .biz - businesses  .info - anyone can register  .name - must register first and last name  .pro - for professionals only  must provide proof  .aero, .museum, .coop are controlled by organizations
  19. 19.  A hostname is any name placed to the left of your domain name which resolves to an IP address.
  20. 20.  The Domain name system is usually used to translate a host name into an IP address.  Domain names comprise a hierarchy so that names are unique, yet easy to remember.
  21. 21.  On your PC, theTCP/IP configuration contains the address(es) of your DNS server(s)  Whenever you use a URL, whether in a browser, or a utility such as ping, DNS servers are used
  22. 22.  Domain Namespaces  Zones  Name server  Name resolver
  23. 23.  The root level domain is "."  Top-level domains include .com, .org etc.,  Second-level domains are often owned by companies and individuals   A subdomain is a further division of a second-level domain  For  There is
  24. 24.  A zone is a part of the domain namespace  A domain, the domain name represents a single zone  For large organizations, subdomains can be divided into separately maintained zones  Each zone typically has a separate DNS
  25. 25.  Zones must be contiguous  can be combined with  cannot be combined with  There must be one primary DNS server in each zone  Each zone can have multiple secondary DNS servers Continue..
  26. 26.  Also called DNS server  The program that stores information about domain namespaces are called name server.  Primary name server (Master)  Secondary name server (Slave )
  27. 27.  Also called DNS client  Resolvers are the clients that access the name server  Used by browsers, e-mail clients, and client utilities such as ping
  28. 28. query for 1. client Root name server Local DNS .in DNS DNS 8. How DNS Works
  29. 29.  Packages  bind,bind-utils  Daemons  /usr/sbin/named  Scripts  /etc/init.d/named  Ports  53/{tcp,udp}  Configuration  /etc/named.conf , /var/named/*  Related  caching-nameserver, bind-chroot
  30. 30.  /etc/named.conf describes the files that configure the zones  Main configuration file  It define access controls
  31. 31.  Default setup is for localhost  In named.conf add the following line zone “" { type master; file “”; };  This allows to be resolved by /var/named/  There can be multiple domains in a single named.conf file
  32. 32.  Also, we can add the following line zone “” IN { type master; file “admin.0.168.192”; };  This allows for reverse lookup for the domain  It uses all or part of the network
  33. 33.  To start DNS  /etc/rc.d/init.d/named start  To restart DNS  /etc/rc.d/init.d/named restart  To stop DNS  /etc/rc.d/init.d/named stop  Make DNS start when you boot Linux  Add the command to start DNS to /etc/rc.d/rc.local
  34. 34. Hackers Loves Linux
  35. 35.  It's available to everyone at a great price .. Hackers never pay for anything.  It is already fully loaded with all the stuff needed, no need to download additional applications for something as silly as netcat.  Open source.. w00t!!! I have full f*#c@i&g control over my OS.  Hackers hate windows compatibility issues/so many libararies.  Hackers don’t want their system to crash or freeze when they’re about to create history.  90% servers run on Linux.. so why should we be behind??  Linux is easy to customization, its customizable in every frigging way, you can update/recompile the kernels too!!This is something we live for, total control is the meaning of our lives.
  36. 36. Speedup internet with Google DNS
  37. 37.  Google Public DNS is a free, global DNS resolution service, that you can use as an alternative to your current DNS provider  Configure your network settings to use the IP addresses and as your DNS servers  Google DNS for  Speed up your browsing experience.  Improve your security.  Get the results you expect with absolutely no redirection.
  38. 38.  OpenDNS    Openic Project    DysDns    Dnsadvantage  
  39. 39.  SafeDNS    Comodo Secure DNS    Norton   Continue..
  40. 40.  Linux is a low cost, flexible, multitasking and highly secured operating system.  It is widely made use in many applications.  DNS is an application that translates names to IP addresses and IP addresses to names  DNS management is a critical part of the maintenance of any Web site. Fortunately, although it can be a little complicated.  Organized in a hierarchical structure  To configure DNS, set up a forward and reverse zone
  41. 41. Prabhakar Thota MSc.,Computer Science The Oxford College of Science