Check which port is opened
 

Hi,
This is my problem , i have a Network of over 300 machine running in various OS,in that i need find the details of a list of opened ports for a specific IP,the reason i'm asking is this somebody having root access to some machine have blocked the ICMP and Telnet and ssh also,i need find those ones .
i can't ping them ,i can't ssh .but i can see that they are in my network

Hi -

"nmap" is your friend:

Here's a good tutorial that covers some of the basic, including checking for open ports:

http://www.certforums.co.uk/forums/thread18698.html

'Hope that helps .. PSM

It really helped .in that i can see some ports are opened ,is that any way that i can telnet into that port and open the other ports like ICMP,I'm not trying to hack the system ,i'm just reinstating what it was before

Try out monitoring tool instead of running nmap for each 500 machines.
"Nagvis" or "nagios" with port specific plugin can fetch you all information on a few clicks.

Sorry i have only command propmt not a GUI

You dont need GUI for that.
Once you setup nagios you can try out on any OS on Windows/ Linux/Unix through web browser.