Networking Basics - IP address, netmasks and subnets

In this tutorial, we will cover some networking basics. We won't be hacking anything, but by the end of the tutorial you'll learn a lot of things which will be useful later, especially when you'll use nmap. Please note that it is advised that you go through wikipedia pages of all the concepts covered here since the discussion won't be exhaustive in any way.

IP address

An IP address is simply a 32 bit address that every device on any network (which uses IP/TCP protocol) must have. It is usually expressed in the decimal notation instead of binary because it is less tedious to write it that way. For example,
Decimal notation - 192.168.1.1
Binary  - 11000000.10101000.00000001.00000001
It is clear from the binary form that the IP is indeed 32 bits. It can range from 0.0.0.0 to 255.255.255.255 (for the binary all 0s and all 1s respectively) [A lot of time, the first octet usually goes upto 127 only. However, we aren't concerned with that here.]

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