best port scanner To scan open port in a network

tanveer · 01-21-2007, 12:50 AM

Hi all:
I am looking for a software that will find all the open ports in a network and what services associated with those ports. Or even find out if a particular port is open in any host of my network?
Thanks in advance.
Waiting for your kind response.

Matir · 01-21-2007, 01:04 AM

You mean something like nmap?

tanveer · 01-21-2007, 01:33 AM

yes. but not sure if those things can be done successfully in a large network.
Please let me know.

chort · 01-21-2007, 05:06 AM

Ehhh, how large of a "network" are you talking about? Nmap performs pretty well for scanning a few thousand addresses, from my experience. For networks larger than that, you're either talking a major corporation, who has enough money to spend on commercial products that do the same thing (most of them have nmap code built-in, but with better management, distributed scanning, etc) or you're talking about scanning The Internet, in which case you shouldn't be doing it.

tanveer · 01-21-2007, 06:40 AM

Hi, thanks for your reply.
I am talking about around 5000 users. So what commercial product will be best suite for this as you are saying it will support thousand users seamlessly? Though I was looking for something free.

Matir · 01-21-2007, 09:02 AM

If you have 5000 users, I would hope your corporation can shell out for decent commercial security software.

chort · 01-21-2007, 01:33 PM

A few from the nmap site
or
Just Google it

You'll see GFI, Qualsys, and Network General over and over.

Matir · 01-21-2007, 01:35 PM

Also, take note that, depending on your needed time frame, nmap can handle very large networks. It's possible (just not fast) to nmap 32,000 machines (trust me).

tanveer · 01-21-2007, 09:19 PM

Thanks for all the help.
First I will try NMAP then, if not possible, will go for commercial products as I wont be searching the whole 5000 users at once.