I need your suggestions of building a network scan tool.

Hi, I'd like to build a network scan tool, which can find out active hosts on the network, their IP addresses, TCP ports etc. But I am not sure how to implement the "ping" functionality, should I implement my own "ping" by using RAW Socket or using a pipe to get the output from the system's "ping.exe" and examine the information that returned.
Since I want this program to work in a fast pattern, so it can scan serveral destination -- ip and tcp ports -- simultaneously, but I don't know whether to use multi-process or multi-thread, I am not sure about the main difference between child process and thread.
Any suggestions will be greatly appreciate!
Thank you!

You can use network sniffing techniqs , LSP , network filter drivers etc.

[Moved thread]

Check out sourceforge, I know that there are a lot of network management tools that are open-source that either coudl provide you with an API that you could then wrap, or that would have exactly what you are already lookin gfor.

Mike, Thank you very much!

"Software is like sex, it's better when it's free." - Linus Torvalds

Does the "father of Linux" really say like this?

Yes, he did. There are theories about the open source software revolution. My 2 cents is basically that, in this day and age, software that is needed in the large-scale will mostt likely be moved to open source. WIll that software be of the quality of a for-profit package? In most cases, from what we've seen so far, the answer is no. Will it cover the basics and do it well? More than likely. So, some things will work open-source, others won't.