I'm looking for a tool that works across windows (xp through 7) that will allow me to open a TCP connection to a specified ip and port. This functionality used to exist in windows xp (netsh diag connect iphost ), but the Netsh diag commands seem to have been removed in vista/7. I've been looking around for something similar, and I've searched Super User, but I can't seem to find anything.

Something that's already built into windows would be ideal, but a small executable that does this (preferably command line, standalone executable).

Edit: I should have specified further. I'm familiar with Telnet and putty, and it is what I currently use, however, I'm in an environment where I have to guide non-technical users through troubleshooting very technical problems over the phone, without any form of remote access (sounds fun, right?). While telnet works, it doesn't explicitly state whether or not the TCP connection was successful; you have to look at the title bar and the contents of the terminal output, which, for some reason, seems to be impossible to users. I'm looking for something with a clear "TCP Connection completed successfully/failed" type response, if such a tool exists.

Edit #2: Thanks to everyone who answered. All suggestions were good, despite the fact that I didn't post as clear a question as I should have. Thanks for the help.

  • Thank you all. Most of these tools I'm very familiar with, and they're what I currently use, however, I'm looking for something that explicitly states it either successfully connected or failed in pretty plain text. Telnet requires you to look at the title of the window and the content of the output, all of which aren't easy to describe to non-technical users over the phone (no remote access). I should have specified this point earlier. Feb 21, 2012 at 20:50
  • I'd suggest you edit your question and clarify / rewrite it. Not all people will read your comment.
    – slhck
    Feb 21, 2012 at 21:09

6 Answers 6



nc mail.server.net 25


socat - TCP4:www.domain.org:80

(Windows version)

Reading socat's examples page never fails to boggle my mind.

  • I'd like to test these further and see the output I get from NC and socat, but I can't at the moment thanks to the wonders of corporate firewalls. Feb 21, 2012 at 21:16
  • I'm accepting this as the answer. Netcat is awesome. I haven't tested the windows version yet, but I played with nc on Fedora 16, and with the -v switch, it's pretty much exactly what I'm looking for. Feb 22, 2012 at 15:06
  • 1
    I found most useful in a shell scripting scenario to use nc -v -w 5 <host> <port> as result output can be compiled and reported nicely. Adjust -w <timeout in secs> value to your environment (this applies to both reachable and non-reachable endpoints and limits the speed of scanning).
    – JGurtz
    May 20, 2014 at 20:33

pkgmgr is now replaced by dism.

Install telnet from command line (run it as administrator):

dism /online /Enable-Feature /FeatureName:TelnetClient

Then you can test TCP connection by:

telnet example.com 80
  • Please read the question again carefully. Your answer does not answer the original question. The OP is asking about Windows and he says he's looking for something other than telnet in his question.
    – DavidPostill
    May 30, 2016 at 11:42
  • 3
    @DavidPostill Sorry, I know. I left my answer because I googled "windows test tcp connection" and this question is on top. I think that many people come here and do not find satisfying solution (look at upvotes for Scott Chamberlain comments).
    – mixel
    May 30, 2016 at 14:47
  • +1 for instruction on installing telnet!
    – Zyo
    Jul 20, 2018 at 2:14

Just use Putty it's tiny (and has a portable app version). It lets you specify port and can use telnet which is a TCP connection. It also has other useful functions like serial connections (no hyper terminal in Windows 7), SSH, And Rlogin. It even has a RAW function that lets establish RAW TCP connections.

Also just so your aware: Telnet is included in XP, you can use it from the command line IE:

telnet mailserver.server.com 25

Which would establish a TCP connection on port 25.

  • I've tried Putty, but how do you get the Putty window to stay open after the remote connection gets closed?
    – Simon E.
    Mar 17, 2019 at 7:20

Late answer, but still a good one:

PowerShell v3

Test-NetConnection google.com -Port 80

Will actually perform a TCP test and provide results:

TcpTestSucceeded : True

I do need to note that PowerShell v3, which has the NetTCPIP module this command needs, does not come installed by default prior to Windows 8. However, you can install PowerShell v3 on Windows 7.

This does not provide a solution for earlier versions of Windows, but for others who land here as I did from the interwebs, it's an easy test tool.

  • If windows xp to 7 was not a requirement in the original aging question, this would be the best modern-day answer, especially because it's built-in. Apr 6, 2022 at 19:16

We used to telnet to a certain port, but telnet does not come with windows 7 anymore by default. So for your USB stick: http://www.drk.com.ar/builder.php

  • 6
    Telnet still comes with windows it is just not installed, however you do not need your windows install CD to install it, in fact just type pkgmgr /iu:"TelnetClient" and it will prompt you with a UAC dialog and it will will be installed. Feb 21, 2012 at 20:51

There used to be telnet in Windows, not sure if that's been removed in later versions. Try looking for it.

You could download Cygwin and run the utilities in there, including netcat and telnet.

There is a Windows version of NetCat available, but I didn't see a canonical URL for it, so I did not include a specific one.


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