Thread: Network Scanner and Network Monitoring Applications Development

Network scanners and cryptography are complicated and complex subjects. First, concentrate on understanding the language.

By Network Scanner, I'm assuming you mean something like port scanner (or maybe something using ICMP or ARP to map out the hosts on a network), and Monitoring means capturing and displaying values of headers in different protocol levels.

Originally Posted by mohitvarma

Is it a good idea to develop such tools using C/C++ which provide you low level access to the hardware or Java can also be used to make such tools ?

It's sort of hard to answer, as generally how you interact with the hardware (network adapters and whatnot) will depend on what the OS allows. There are system calls available in C in Linux that allow you to set adapter settings as well as various options for different protocol levels. Also Windows allows you to do this, but there are different capabilities that might not be available without 3rd party libraries.

Originally Posted by mohitvarma

PS: I do understand that there are many such applications available, however, I want to understand them for my own learning.

You will need to have good understanding of the language first, also network theory and a solid grasp of the different capabilities of the API you are using will be required.

Of the language you will need knowledge of basic types, flow control, structures, pointers, allocating memory, bitwise operations, type casting, and many other things. Of network theory, you will need to know the header fields of the protocols you will use, and what they all mean. Of the API you will need to know how to set the options you want for the protocol levels and creating the type of socket you want, as well as how to send and receive the data structures that represent network protocols.

As a comparison of the time required, it took me several months of studying network theory and API functionality before I was comfortable enough to write programs with lower level protocol access on my own. This was with me already knowing enough of the language to use these things. Even then my capabilities are quite basic and require having several references nearby on the protocols I'm using.