Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

I used to use netcat for Windows to help track down network connectivity issues. However these days my anti-virus software (Symantec - but I understand others display similar behaviour) quarantines netcat.exe as malware.

Are there any alternative applications which provide at least the following functionality:

  • can connect to an open TCP socket and send data to it which is typed on the console
  • can open and listen on a TCP socket and print received data to the console

?

I don't need the 'advanced' features (which are possibly the reason for the quarantining) such as port scanning or remote execution.

share|improve this question
add comment

7 Answers

http://joncraton.org/blog/netcat-for-windows

This person ran into the exact same problem; read till the end for the version compiled without remote execution. I downloaded and extracted these on two systems running 'Symantec Endpoint Protection'. While the netcat on this page was removed and quarantined when run, the 'rodneybeede' version linked to near the end of the page tried to connect to the desired port, and wasn't quarantined.

share|improve this answer
    
Yes, note that this site has a download with a "non -e" version that apparently is more friendly for virus scanners. –  rogerdpack Jun 10 at 14:59
add comment

I discovered that MobaXterm for Windows has the nc (netcat) command, as well as many other Unix commands, like ls, ps, and kill.

I wholeheartedly recommend MobaXterm, especially if you are familiar with both Unix and DOS. For me, there was nothing to install; it's just one executable that opens a terminal window in Windows that accepts many Unix commands. Since I frequently use both Unix and DOS and often use one to connect to the other, MobaXterm for Windows is an extremely useful tool for me.

(Sorry if this sounds like an advertisement; I don't work for nor am I affiliated with MobaXterm. A friend recently introduced it to me and it made certain tasks so much easier for me.)

share|improve this answer
    
I believe this is just the "cygwin" netcat, and installed to a temp folder, so not accessible outside "MobaXterm" [however, it does work from inside its shell]. –  rogerdpack Jun 10 at 15:03
add comment

The quick answer here is to use the built in Telnet program from the CMD command line.

the command is...

telnet hostname.domain.com 80

The above example will connect you to the hostname on port 80. you can use it on just about any port you need to check out. This is extremely handy for troubleshooting SMTP and ESMTP issues.

share|improve this answer
5  
Yes telnet is useful, but only solves half of the problem. –  heavyd Jul 28 '09 at 15:43
    
This will only allow me to do the first of my bullet points, won't it? Also doesn't telnet expect some sort of handshake communication from the socket it connects to? –  Matthew Murdoch Jul 28 '09 at 15:44
4  
You no longer have telnet on win vista. –  Mercer Traieste Jul 28 '09 at 16:07
1  
But you can install it, according to (for example) adamsdvds.co.uk/tutorials/vista/telnet/telnet.php... –  Matthew Murdoch Jul 28 '09 at 16:23
1  
@Axxmasterr my version of telnet (Windows XP) doesn't seem to support a 'listen' mode. –  Matthew Murdoch Jul 28 '09 at 16:57
show 5 more comments

If you need netcat, you can whitelist netcat.exe in your anti-virus program.

You may also want to download a current version, which is called ncat and can be found in the nmap distribution.

share|improve this answer
    
unfortunately "ncat" (the command line executable provided by the nmap distro) doesn't seem to be a drop in replacement for the unix "nc" command [different command line parameters] <sigh>...you have to get a true "netcat" somewhere else [or use cygwin] –  rogerdpack Jun 10 at 15:13
add comment

Even if it seems otherwise, Wireshark is easy to use. You can setup it easily to listen to a specific port.

wireshark

Another tool is nmap which again, I find easy to use. It will tell you much about open ports on a remote machine, so you can use it troubleshoot connectivity issues. Just nmap www.google.com from command line, or from included gui interface.

nmap

nmap

Just give them a try.

share|improve this answer
    
Will these tools let me 'open and listen on a TCP socket and print received data to the console' (the second bullet point)? –  Matthew Murdoch Jul 28 '09 at 16:17
2  
I've updated the answer with a screenshot of tcp capture from Wireshark. In 9 minutes i've downloaded it, installed it, started a capture, and gave it a screenshot. –  Mercer Traieste Jul 28 '09 at 16:28
1  
But isn't Wireshark capturing data sent between two already executing networked processes? I really want to be able to start up the application to listen on a port as a server (as I could with netcat) so that I can debug client applications. –  Matthew Murdoch Jul 28 '09 at 16:48
3  
Wireshark will not allow you to communicate with the server you are connected to, nor will it listen on socket for incoming connnection. It is a packet capture tool, not quite what the OP is looking for. –  heavyd Jul 28 '09 at 17:19
    
Will WireShark let me capture data between two processes running on the same machine? –  Matthew Murdoch Jul 31 '09 at 8:35
add comment

ncat seems to be exactly what you're looking for. It's an implementation of netcat available on the official nMap site with the port scanning feature removed. Doesn't raise any virus alerts either.

From the user guide:

Ncat is our modern reinvention of the venerable Netcat (nc) tool released by Hobbit in 1996. While Ncat is similar to Netcat in spirit, they don't share any source code. Instead, Ncat makes use of Nmap's well optimized and tested networking libraries. Compatibility with the original Netcat and some well known variants is maintained where it doesn't conflict with Ncat's enhancements or cause usability problems. Ncat adds many capabilities not found in Hobbit's original nc, including SSL support, proxy connections, IPv6, and connection brokering. The original nc contained a simple port scanner, but we omitted that from Ncat because we have a preferred tool for that function.

share|improve this answer
add comment

You can download Ncat - Netcat for the 21st Century. It seems to be a modern version of NCat, it is actively supported, and, most important, it had a 0/48 detection ratio at VirusTotal.

The only caveat is that the Windows binary is distributed as part of the whole NMap Windows installer - you can't download it separately, but you can disable anything else from the install wizard:

enter image description here

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.