Netcat is a simple but powerful utility program that reads and writes data across network connections, using TCP or UDP protocol, IPv4 or IPv6, with a variety of functions.

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Netcat connection over dynamic IP

I was playing around with netcat on my lan , had PC1 configured as a netcat client and PC2 configured as a netcat server into a reverse netcat TCP connection.This whole reverse TCP connection works ...
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how to bypass this error : “port range not valid”?

I have a port number that I want to connect to it via net-cat. previously I was working with windows and it was working perfect; but now in Ubuntu when I want to run the Net-Cat it's show me this ...
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150 views

Two hop SSH with multiple user names

I am trying to set up an ssh proxycommand, where the user name at the final host is different from the user name at the original host. I am logged in on firstHost as username and want to effectively ...
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1k views

Cygwin netcat nc doesn't resolve hosts through /etc/hosts

I'm trying to use ssh to log into remote servers, and I have a ProxyCommand setup in ~/.ssh/config to use a proxy (setup through PuTTY to connect to a VPN). The ProxyCommand uses nc to connect ...
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713 views

Can I stop a netcat tar pipe and continue later without overriding existing files?

I'm trying to copy a lot of files from my NAS to my server, about 2TB. I found that using a netcat tar pipe to copy the directories goes pretty fast, about 40mb/s. It seems to work faster than rsync ...
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139 views

How to upload a file to windows through a netcat session

I have a netcat session and I want to upload a binary to the target windows machine. How can I do so? Is there a native "wget" in windows?
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494 views

Simple secured SFTP tunnel?

I'd like to setup an sftp tunnel so that I can connect to an IP-secured SFTP server through a gateway computer from anywhere, and download the files to anywhere. I was thinking of using a combination ...
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896 views

Bash RTSP client with netcat - keep connection open while parsing sent data with sed?

I am trying to make a RTSP client in bash. Problem is that I must make only one connection to the server through which it will send video frames. I can keep it on one connection up to the point at ...
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52 views

How to keep the reverse shell open in Netcat?

As soon as the command prompt is closed on the target machine the reverse shell is closed on the client machine. Is there any way to keep the port open and Netcat working after the target machine ...
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32 views

How to netcat all the files in my directory?

I have a directory of files I'd like to netcat to another machine. For one, I use nc <ip> <port> < sample.fls But if I have a directory of sample1.fls sample2.fls sample3.fls ...
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2k views

Why is the '-e' option missing from netcat-openbsd?

Why is the -e option missing from the netcat-openbsd package? There is a netcat-traditional package but it has many features from the OpenBSD package missing. I am running Linux Mint 16. Does anyone ...
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44 views

How do I make netcat timeout nonsilently?

I'm trying to send some data to a server with a command like nc -w 3 IP_ADDRESS PORT < data where nc is the netcat from FreeBSD 5.4. When the server doesn't respond within 3 seconds I get no ...
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2k views

Netcat error: Can't grab 0.0.0.0:80 with bind

When I tried to listen on port 80 in Windows 7 with netcat, I get this error: C:\Users\sashoalm>echo "hello, world" | netcat.exe -l -p 80 Can't grab 0.0.0.0:80 with bind On the other hand, ...
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322 views

How to send message both to netcat and other script?

I'm trying to make some client-server interface. Think of it as one-on-one chat. What I want to achieve are two horizontal views. Bottom for my (server) input, top for client output and my input. ...
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656 views

Unable to transmit stream through OpenVPN tunnel

We are trying to transmit a video-stream via netcat from a OpenVPN server to a client. The server is a Raspberry Pi with Pidora running on it. The client is a Notebook with Ubuntu 12.04 and has a ...
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56 views

Is it possible to set up my own DNS for my computer?

I don't know if I ask the right question but I hope this situation would give you the whole picture. I have my PC which located at my apartment. As usual, I get access to Internet using service ...
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1k views

How to send a binary message in TCP and store the response

I have to develop a client for a proprietary protocol and it would be very useful to be able to understand the behaviour of the existing server by sending it custom messages and look at the answer. ...
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129 views

Knock on a port to get service and version

I'm having difficulty remmebering a certain command I would use in bash that would give information about a port it would 'knock' on. I've used ssh backdoors before so that I can access my home ...
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1k views

Can I use nc and/or stunnel to make a transparent SSL proxy such that I can specify the outgoing source port?

I've been playing around a bit with different variations and can't seem to find something that quite works. I want to be able to 'bridge' an SSL connection across a particular gateway node in the ...
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3answers
1k views

Using nc (netcat) to emulate NTP server response

I want to test some security on an NTP client developed in-house and would like to use netcat to do it. I have packets captured with Wireshark from previous NTP exchanges that I tried to feed to the ...
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1answer
618 views

How to purge connections left open by SSH ProxyCommand?

I have a webserver WWW1 and a front-facing proxy PRX. I use SSH ProxyCommand to connect to WWW1's internal IP (private IP) via PRX (private+public IP). For some connections (not all) I see a network ...
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1k views

nc or socat: How to read data from remote:/dev/ttyACM0?

I have a device running at a remote computer on /dev/ttyACM0 Now I want to read that data on my computer. I can connect to it over ssh. Unfortunately I am a nc/socat rookie and no howto covered this. ...
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24 views

How to store data from different netcat connections in separate files?

I need a server that should receive data streams, store them in files and send further. Each connection should create a file with corresponding timestamp in file name, then write to it. My solution: ...
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18 views

nc and named pipes for port forwarding

I have my environment setup to listen to jetty on port 8888. However, for a limited time, I will have to also listen on 8889. I though of using named pipes and nc for that: mkinfo pipe1 /bin/nc -l ...
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34 views

netcat between mac and linux only working in one direction

I have two machines on the same local network. One is a Mac (192.168.42.74) and one is a Dell (192.168.42.75) running Kubuntu Linux. If I issue 'nc -l 12345' on the Mac and issue 'echo "blah" | nc ...
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50 views

Creating a proxy with netcat

I'm trying to setup a permanent proxy server for one of my servers to reroute connections having issues. The proxy server is running Centos 7 x86 User -UDP or TCP-> Proxy -> Server I am am ...
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99 views

automatically start netcat on localhost and remote-host and keep it active

I found this answer by @jeremytrimble on Stack Overflow which explains how you can read a FIFO file over network. I wonder if it’s possible to start these netcat commands automatically, e.g. in a ...
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60 views

Bash - Parsing XML output of nmap

I am trying to write a bash script that will take port id I retrieve from an nmap command, and then use those ports to send a file using netcat. So I got some basic knowledge using this link, How can ...
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38 views

Give a command HTTP proxy auth access

I'd like to let a command (wsimport) access a URL through an HTTP proxy with authentication. It can be configured to use a proxy, but not with auth. I was wondering if a tool such as netcat, or any ...
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37 views

How to connect two debian VMs using vmware workstation so that one acts as a web server and the other as web client

I want to connect two virtual machines running using VMWare workstations - Debian Linux and I have setup private DNS server on one VM named "Server" and other VM is named "client". I am trying to ...
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24 views

How to send OUTGOING to 1 netcat connection whilst reading INCOMING in a while loop?

I'm currently using netcat to grab the incoming lines of data with following: nc 192.168.1.1 1234 | while read line; do echo $line done I need to send outgoing data to the same connection, ...
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21 views

OS X LoginHook - nc exits prematurely for no apparent reason

I'm trying to use loginhook to download large amounts of data and I've been having problems which I've nailed down to nc exiting prematurely for no apparent reason. This is a simplified test script: ...
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43 views

SImple server to run program and return result

I am attempting to create a minimal local listen server that takes an input request, pipes the input to a program and then returns the result of the command. What I have at the moment is the program ...
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52 views

Port bridge with iptables

is there a way to achieve the same thing than bidirectional socat functionality with nc mkfifo backpipe nc localhost 42042 0<backpipe | nc localhost 1042 1>backpipe But only by using iptables ...
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44 views

Netcat doesn't detect open port with ngrok

I'm using ngrok 5002 to open up a port on my computer. I then do netcat -z xxx.xxx.xx.xxx 1-65000 with xxx.xxx.xx.xxx being my external ip I found via some web service. However, I expected ...
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100 views

Netcat redirect remote console application

I have a windows interactive command line application ('pianobar', Pandora client) that I'm running on a Win2k8 server that I would like to control remotely, possibly using netcat. I need to be able ...
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355 views

Why is Udcast is many times faster than Netcat?

I use Netcat once in a while to copy files or disk images over the network. While it does the job I always felt like it was always on the slow sluggy side regardless of using ssh, no ssh, compression ...
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279 views

Netcat: Should I use Ctrl+C to close the connection?

I've opened netcat, and I'm entering things from the keyboard. When I've finished and I want to close the connection, should I just hit "Ctrl+C"? I want the connection to be closed "normally", but I ...
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225 views

netcat command is not working in bidirectional mode

I am using netcat in Linux to send and receive data (using udp protocol) from a serial port to another device through the network. The command is : nc -u 192.168.10.12 < /dev/ttyUSB0 > ...
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278 views

Keep Process Running after Quitting NetCat

I am using NetCat on Windows 7 Professional to connect to my linux machine at home. I need to run a process and make it keep running after I close NetCat (Cmd Console). However when I close and then ...
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2answers
256 views

Is it possible to push video out and usb over TCP/IP

I have a security camera system that is running Linux and is placed near the cameras (not in an office). It has a VGA out and uses a USB mouse. I'd love to redirect the VGA and USB to another ...
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2k views

Server: Microsoft-HTTPAPI/2.0 running on port 10234 on my Windows 7 pc?

I've recently set up a home server and spent some time working on the security. One of the tools I've been using nmap which I pointed at my Windows 7 desktop. It showed an unknown service on port ...
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1answer
598 views

TCP connection to my host's public IP address using Linux netcat

I need to make a TCP connection to my machine through an application that needs only the public IP address and port to connect. I have been able to do it in Windows, but I need to do it in Linux ...
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2answers
1k views

How do I send and receive simultaneously with netcat?

I need to test a TCP server by connecting with netcat as a client sending a stream from /dev/random and at the same time pipe the output to /dev/null. Receiving: nc 127.0.0.1 3000 > /dev/null ...
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2k views

How do I make netcat receive UDP packets from any host?

Is there a way to make netcat receive UDP packets from any ip:port? I don't want it to bind to a specific host as the first packet comes. I can consider alternatives, but they have to be bash ...
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1k views

netcat and tee redirection via a bash script

Quick question that has been haunting me all day.. I have a bash script that includes this line: nc -l 8044 | tee nc-output & The output from netcat is never being written to nc-output. If I ...
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1k views

Port forwarding on D-link DIR-615 router

I'm attempting to configure my router to forward a port to my Linux machine. The Linux computer has a static IP (192.168.0.185) Right now I'm just experimenting to make sure I can forward a port, so ...
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299 views

cat file that contains escaped characters to netcat

I'm trying to test a webserver with some HTTP request written in a file. GET / HTTP/1.1\r\n\r\n Right now I'm feeding that file to netcat like this: cat files | nc localhost 80 However, the \r\n ...
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622 views

Meaning of “netcat can be used as a backdoor” [closed]

I recently read about netcat and it is often mentioned that it could be used as a "backdoor". What exactly is meant by backdoor? Could some one give an example of such usage of netcat.
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55 views

Quickest way to upload to a server?

I am looking for a way to upload a large file (1gb) to a server. So far I have used scp, nc and sftp. Initially I start with a nice upload speed of around 2 mbps, but this quickly slows down to around ...