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Questions tagged [netcat]

Netcat is a computer networking service for reading from and writing network connections using TCP or UDP

293 questions
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convert a hex string to binary and send with netcat

I have a binary file that I can send with netcat: $ nc -l localhost 8181 < my.dat The file contains this: $ xxd my.dat 0000000: 0006 3030 3030 4e43 ..0000NC What I really want to do is send the hex string directly. I've tried…
Chris Snow
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How does netcat know if a UDP port is open?

So I can use this netcat command to check if a UDP port is open: $ nc -vz -u 10.1.0.100 53 Connection to 10.1.0.100 53 port [udp/domain] succeeded! Unlike TCP, UDP is connectionless (fire and forget). So at a high level does anyone know how netcat…
Patrick McMahon
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What are the differences between ncat, nc and netcat?

I'm not sure about when to use nc, netcat or ncat. If one is the deprecated version of another? If one is only available on one distribution? If it is the same command but with different names? In fact I'm a bit confused. My question comes from…
Pozinux
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/dev/tcp listen instead of nc listen

With a netcat listener like: nc -l < ~/.bashrc I can grab my .bashrc on a new machine (doesn't have nc or LDAP) with: cat < /dev/tcp// > ~/.bashrc My question is: Is there a way to mimic the capabilities of nc -l in my…
h3rrmiller
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No route to host with nc but can ping

I'm trying to connect to port 25 with netcat from one virtual machine to another but It's telling me no route to host although i can ping. I do have my firewall default policy set to drop but I have an exception to accept traffic for port 25 on that…
Katz
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3 answers

Using netcat for port forwarding

I have a process that listens on an IP:port - in fact it is spark streaming which connects to a socket. The issue is that I wish to somehow create a server that connects to spark on one port and data is streamed into this server from another port.…
disruptive
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Netcat - How to listen on a TCP port using IPv6 address?

I am using the newest version of netcat (v1.10-41.1) which does not seem to have an option for IPv6 addresses (as the -6 was in the older versions of nc). If I type in nc -lvnp 2222 and check listening ports with netstat -punta, the server appears…
bashbin
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netcat doesn't print response

I'm trying to send commands to a tcp port using netcat and pipe response when I run netcat and type my command it prints response correctly but when I pass command from a pipe it sends the command correctly but doesn't print response So, this…
Ariyan
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netcat: send text to echo service, read reply then exit

I would like to use netcat to send a piece of text to the echo service on my server, get the reply then exit, so that I know the connection is still good. so far I've tried: echo 'test' | netcat server 7 this way netcat would wait for more…
SparedWhisle
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SSH speed greatly improved via ProxyCommand - but why?

The TL;DR version Watch this ASCII cast or this video - then come up with any reasons why this is happening. The text description that follows provides more context. Details of the setup Machine 1 is an Arch Linux laptop, on which ssh is spawned,…
ttsiodras
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netcat doesn't terminate when stdin closes

I'm trying to send a message through netcat. After sending the message, netcat must terminate. I've tried the following: cat tsmmessage.bin | nc -u localhost 4300 nc -u localhost 4300 < message.bin The -q option states: -q seconds after EOF on…
Frank Kusters
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Remote desktop over SSH reverse tunnel to replace TeamViewer

I want to open a remote desktop session from my laptop to desktop over my SSH (reverse) tunnel. That should be simple (or at least doable), right? Until now I've been using Team Viewer to log in to the remote desktop. I'd like to achieve similar…
MountainX
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Simplest way to send files over network

What is the simplest and most versatile way to send files over the network to other computers? By that I mean computers that other people are using at the moment. I don't think SSH works if the computer has an active session open. So far I am using…
TomTom
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netcat in shell script giving invalid connection

I have a shell script that uses netcat to listen to localhost on port 1111 for web requests. Every time I try accessing localhost:1111/index.html for example I get: invalid connection to [127.0.0.1] from localhost [127.0.0.1] 60038 the number at…
MinaHany
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Using in/out named pipes for a TCP connection

I've been fiddling with getting this to work for a while now, so I suspect some sort of fundamental misunderstanding about how pipes work is the root cause of my troubles. My goal is to initiate a TCP connection to some remote host via netcat and…
noffle
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