Finding Open Ports on a LAN

Hey all,

First off, let me just say, I am not trying to obtain information that I will later turn around and use to hack with. I am a member of my company's IT department and we just want to be able to type in a certain port number (i.e. 2209 or 7834) and return all of the computers that have this open port. This is basically so we can see if someone has a certain Server application running like SQL Server or MySQL or something like that. We know it is happening, but the people that are doing it do a pretty good job at hiding it, but you can't hide a port number. If anyone has some information that would be helpful please post. Thank you for your time.

Mark

You are effectively doing a TELNET <computername> <portnumber>.

You could do this using a DOS command sent from the VB app.
Or you could look up what Telnet is doiing with Winsock from places like this forum or www.winsockvb.com

duhh.....I knew it was something simple. Isn't it always?? Thanks a bunch, the telnet idea works great, now I just need to capture the data coming back to see if it connected or not.

Thanks again.

Ok guys,

I am thinking the best way to do this will be to Shell(telnet.exe IP Port) but I am not sure how to capture the returned text. Anyone have any ideas??

You need to shell Command.com to get output re-direction.

I.e.:

VB Code:

Shell "Command.com /c Telnet.exe 10.44.23.123 80 > c:\temp\Results.txt"

Then you can open and look at the resulting file.

But whether this will work with Telnet, I am not sure. You might find that the Telnet.EXE application has its own output stream. Test it on a DOS window first.....