There is no way to get the IP's of connected PC's with plain TCP/IP.
You can try "pinging" every possible IP on a network for a well-known service, but this is considered by most network administrators to be a hostile attack. Not to mention it would fail if the clients do not provide whatever service you are pinging for.
If you really want to get information on the network, either have your clients volunteer the information by registering with a central server when they start up or use a protocol which permits discovery, like Jini/Apache River
nmap can get some of that, but it is hit and miss, such as OS and network detection. When it works you can get versions from it.
As for size of RAM, and things like that, you probably can't directly. Doing things like this are very "noisy", and if you don't have permission then it could land you in very hot water. You you are lucky, all that will happen is you lose your job.
If you have legitimate need, you could write a little server and push it out that collects these details and passes it to you, of course this is dangerous, you don't want to make hacker recon too easy.
I can't think of a legitimate reason why would would need to do get all this information in this manner. If you have a legit need to know it, you will have access to records, and possibly the machine itself. If you were security testing, the amount of RAM would be pretty worthless information, IMO.
"Computer science is no more about computers than astronomy is about telescopes" - Edsger Dijkstra
I have a need for knowing the amount of RAM for trouble shooting clients trying to stream high quality video, but not knowing enough about their PC to tell me how much RAM they have. Is there a way to get this information in any form or fashion?
Joined: Jan 03, 2006
Yes, ask your clients for the information. You can walk them through the steps to find it.
subject: how to get system information(like ram size,OS,OS version) using ip address in java