Utility to open TCP port to listen state

Question

Is there some basic utility to open a specific network TCP port on my machine?

I need to test how my program deals with ports in the listening state.

Solution 1

netcat should do what you want. Have it listen on you machine and echo stuff to STDOUT:

nc -4 -k -l -v localhost 1026

when you want it to close when the connection ends, don't use -k

Solution 2

You have

TCP Listen: http://www.allscoop.com/tcp-listen.php

Port Peeker: http://www.linklogger.com/portpeeker.htm

Microsoft's Command-line utility Portqry.exe

Solution 3

Try iperf. There is a version for Windows. You can just run it like iperf -s -p 1234, and it will listen on port 1234. You can then connect to that port from a remote machine by doing something like:

telnet 192.168.1.1 1234

iperf -c 192.168.1.1 1234

portqry -n 192.168.1.1 -e 1234

You would need to obtain iperf.exe or portqry.exe for the last two. iPerf isn't strictly designed for this task, but it's great for troubleshooting connectivity, bandwidth availability, stress testing links, etc.

Solution 4

It looks like this utility will do exactly what you want, even displaying the received data if you like: http://www.drk.com.ar/builder.php

It has a GUI rather than just a command line, an advantage for some.

Solution 5

The netpipes tools faucet and hose have always served me well, simplifying stdin and stdout for my programs to use over the network.

Similar to netcat.

Ubuntu description:

The netpipes package makes TCP/IP streams usable in shell scripts. It can also simplify client/server code by allowing the programmer to skip all the tedious programming bits related to sockets and concentrate on writing a filter, or other service.

EXAMPLES
       This creates a TCP-IP socket on the local machine bound to port 3000.

       example$ faucet 3000 --out --verbose tar -cf - .

       Every  time  some process (from any machine) attempts to connect to port 3000 on this machine the faucet program will fork(2) a process and the child
       will exec(2) a

       tar -cf - .

View more solutions

Comments

[Diogo]

It works on Windows??? I tried this command here and it was not recognized.

[cutrightjm]

I was going to post this as my answer! =p You can download netcat here: joncraton.org/files/nc111nt.zip It's a pretty old tool, but I think people failed to realize just how useful it can be.

[cutrightjm]

@Diogo Rocha You know it is a downloaded program, correct?

[Diogo]

I didn't know... It would be nice if the answear post the link to download then...

[Florenz Kley]

@DiogoRocha - I removed the bogus link to netcat. The official site is at sourceforge. It's part of pretty much every packaging repository out there, so I have not installed in from source for like 10 years in a row.

[Diogo]

Sure, no problem.

[Vic]

Looks good, but the antivirus won't allow me to install neither the "regular" nor the "safe" version of nc for windows.

[Florenz Kley]

humor me - since when when does Wireshark actually behave like a service listening on a port? It passively records the traffic.

[Florenz Kley]

@Vic - time to make friends with your admin, then... or maybe time for that Linux or BSD virtual machine where you find more tools for network programming you ever dreamed of :-)

[Breakthrough]

@FlorenzKley you're right, it doesn't... I interpreted his question as how to view the network traffic on a certain port though, since wouldn't it be trivial for the O.P. to just run two copies of his program at once on the same port (to see what happens if another program is already listening on the port)?

[cutrightjm]

@FlorenzKley If you are saying that my link is bogus, you are mistaken.

[Vic]

Thanks, but I need it for Windows...

[Marcos]

Not even Cygwin?

[hoggar]

TCP listen - nice little GUI program without installation! ;-)

[Vomit IT - Chunky Mess Style]

Does this tool allow the opening of TCP port on the machine it is running?

[Patrik Mihalčin]

I'm not aware of that.. it's just a view as the name suggests

[Mokubai]

Note: some malware or firewall security software might flag this file as a virus. Due to what this program can do it may have been included in malware programs but it is not malware itself and as of 2017-10-04 this file is scanned as clean by VirusTotal (marked as "riskware" by only one scanner). See the Community note on the url and the File scan itself

[sina nazari]

Port Peeker, site no longer exists or is not reachable (Jan 2019)

[nelson.t.cunha]

Here you go, InternetArchive's latest snapshot: web.archive.org/web/20180616055542/http://www.linklogger.com‌​/… Some download links are still working.

[Peter Mortensen]

But the question is/was: "Is there some basic utility to open a specific network TCP port on my machine?". In TCPView you can close a connection, but that is the only thing that can be changed in the system.

[ImaginaryHuman072889]

TCP listen for the win. netcat was a very complicated installation. TCP listen is one exe that doesn't require any installation.