Gaurav Kansal Blog

IP or Internet Protocol, is the primary network protocol used on the Internet, introduced by Vint Cerf and Bob Kahn in 1974. IP version 0 to 3 was introduced and used between 1974 and 1979. After changes and refinements in initial IP protocol, version 4 was introduced in 1981, commonly known as IPv4, described in RFC 791 , which become the backbone of Whole Internet in no time. (IPv4 is know as v4 because it is the fourth version of IP not because it has 4 octets, which is a common myth). TCP/IP Protocol was designed as a part of project ARPANET, whose aim was to interconnect various universities and research institutes of USA. But with the dot com boom, TCP/IP grows like anything and its become a victim of its own success. In Early 90's, expert realized that we will exhaust the whole IPv4 number very soon and there is a need for a new protocol, which should be enough in size to serve the internet community for at least 30-40 years. This lead to new version of Internet Protoco

Best Current Practices in for IPv6 Address Allocation This Best Practices document aims to provide IPv6 Address allocation guidelines that a network operator can follow while planning the IPv6  sub-netting  for its network (based on the issues faced and learning’s from IPv6 implementation in NKN and NIC network). Best Current Practice: 1. Sub-netting         IPv6 addresses generally written in Hex format. Each Hex number represents 4 bit, commonly known as nibble. A nibble boundary is a network mask that aligns on a 4-bit boundary. Sub-netting the v6 address at nibble boundary improves efficiency and make it easier to understand for humans* (Machine will anyway read it binary format  J ). Example of Nibble and non-Nibble Boundaries Sub-netting From the above example, we can clearly see that Sub-netting at the Nibble boundaries is easier to manage and do the sub-netting. * Condition may arise where you may have to

DIG is a command-line tool for querying DNS Name Server (similar to nslookup utility available in Windows and host utility). dig utility can be used for querying DNS about the host address (both A and AAAA), name server(NS), mail exchange(MX), Pointer Record(PTR), SOA (Start Of Authority) and others. DIG is a part of BIND software package ( BIND package is developed and managed by Internet Systems Consortium ISC). Usage Example :- 1. Ask for a host address :- dig nkn.in 2. Ask from a specific server :- dig nkn.in @8.8.8.8 ; <<>> DiG 9.8.5-P2 <<>> nkn.in @ 8.8.8.8 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 13527 ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;nkn.in. IN A ;; ANSWER SECTION: nkn.in. 14103 IN A 164.100.56.206 ;; Query time: 171 msec ;; SERVER: 8.8.8.8#53 (8.8.8

DIG is a domain query tool and a part of BIND package of ISC. Using dig is very simple in Linux but is little bit tricky to use the same in Windows. I have tried to do the same and sharing you the steps which i follow for configuring the dig in my windows machine. How to install dig in Windows :- 1. Create a folder for dig (eg: C:\dig) 2. Download the latest version (currently which is 9.8.5-P2) of BIND software from  here  (ZIP format) 3. Extract the .zip file and copy the dig.* and *.dll files in the folder created in step 1 4. Add the folder in the Environment Variables path settings (Right click on My Computer --> click on Properties --> Advance System Settings --> Environmental Variables --> Path ) Use dig more efficiently (using .digrc) :- dig gives lot of information in its output which may not be useful in most of cases (and may be annoying for some of us). To cut short the dig output to show you only the answer section, you need to give lot of pa

There was a time when we use to get  a call from marketing companies selling blah-blah products and these calls were the last call we want to receive. Then comes a  National Do Not Call and we get a rid of these marketing calls. But what about internet. Big internet marketing companies (like Google and others) whose business base is marketing and selling ads are tracking us. They track every site we visit, how much time we spend on each site, our search preference and based on state-of-art algorithms there robots decide what ads we will receive. Google do the same thing through gstatic.com domain. If you do the packet trace when you do the browsing, you will find the significant traffic from gstatic.com although you haven't ask anything from that domain. Document on gstatic.com which itself talk about  Advertisement  . Will we wait for government DND type initiative or we will do something by own to protect us. They are many browser extensions available freely in marke

National Knowledge Network The NKN is a state-of-the-art multi-gigabit pan-India network for providing a unified high speed network backbone for all knowledge related institutions in the country. The purpose of such a knowledge network goes to the very core of the country's quest for building quality institutions with requisite research facilities and creating a pool of highly trained professionals. The NKN will enable scientists, researchers and students from different backgrounds and diverse geographies to work closely for advancing human development in critical and emerging areas. Features: NKN is designed as a Smart Ultra High Bandwidth network that seamlessly interconnects the leading Scientific and Technological institutions - which are pursuing world-class research and development. NKN design is inherently proactive; it takes into account the requirements that may occur in the near term and long term. Some of the salient features of the NKN are: ·  

What is Wi-Fi?                                                                                                                  Wi-Fi is the name of a popular wireless networking technology that uses radio waves to provide wireless high-speed Internet and network connections. Wireless networks operate using radio frequency (RF) technology, a frequency within the electromagnetic spectrum associated with radio wave propagation. When an RF current is supplied to an antenna, an electromagnetic field is created that then is able to propagate through space. The cornerstone of a wireless network is a device known as an access point (AP). The primary job of an access point is to broadcast a wireless signal that computers can detect and "tune" into. The radios used for Wi-Fi communication are very similar to the radios used for walkie-talkies, cell phones and other devices. They can transmit and receive radio waves, and they can convert 1s and 0s into radio waves and

A Root name server is a name server for DNS root zone. Every new DNS query resolved by our local resolver first goes to Root Name Server and then root name server directs it to required domain server. This means that if in any case, root name servers goes down, then whole internet goes down (don't worry this cannot be done so easily as most of root name servers are running on Anycast and located all over the world). Recently, an anonymous group posted, to target these 13 root name severs and to bring them down by DDOS attack on 31st March 2011, to protest against SOPA and PIPA. But as expected, they didn't succeed. The last time someone seriously tried to take out the root servers was about 4 or 5 years ago and they managed to take down six out of thirteen servers. I am not saying that it could not be done but it would be tough. Every root name server is operated by different organization (except 'A' and 'J' which are operated by VeriSign) but they all po