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 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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60 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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299 views

nc connection refused even on loopback

I'm working on an embedded linux system, which appears to be networked correctly and is running ssh (dropbear) and rpcbind. I'm setting up a server application on it, and every single thing I try ...
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1answer
381 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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1answer
658 views

X11Forwarding using SSH and Netcat

From my machine, I must connect through nodes A, B, and C, to reach target: localhost -> A -> B -> C -> target Machine A is configured to refuse X11 Forwarding, so I guess I shouldn't ...
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2answers
914 views

Why can't nc / netcat sniff http port traffic easily?

I'm NOT looking for advice such as "try wireshark." I'm trying to understand what netcat is and isn't. When I try to listen (-l) to port 80, it says "address already in use." Can netcat not listen to ...
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1answer
98 views

DDNS and NetCat

I'm messing around with netcat(windows) and i'm trying to configure netcat listening to external connections.My ISP provides me dynamic IP so i gotta find a way to have netcat connecting back to me no ...
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1answer
187 views

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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1answer
12k views

Can I pipe/redirect a console application through netcat so it can be used remotely?

Is it possible to 'pipe' an instance of a console application through netcat, so netcat is listening for a new connection and redirects the stdin and stdout over the network connection.
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2k 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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1answer
540 views

netcat output into separate files using string delimiters

I want netcat to pipe the output of a tcp/ip connection to commands that examine the output and split it into distinct files separated by the strings "msg" and "/msg" from the output, something like ...
2
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3answers
529 views

Use xargs to send requests to the same server in parallel with netcat

I am trying to devise a one-liner to send text to a simple echo server - but multiple connections in parallel. This is what I'm trying: echo -e A,B,C,D | xargs -d, -i -P 4 echo {} | nc localhost ...
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2answers
603 views

Netcat stops when in a detached session

I want to use netcat to dump a number of blocks of strings to a file. I've been running this in my linux terminal and everything works very well until I try to detach my command line. If I run my ...
2
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1answer
323 views

ncat only works in certain scenarios

I tried using ncat (a “much-improved reimplementation of netcat”) to chat with a friend (and ultimately want to send a large file, but I know I can get that working once I get chat to work). We both ...
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2answers
323 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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2answers
1k views

List incoming connections on nc (netcat)

I set up nc on some computers in my office. They're connecting to our server like so: nc 192.168.1.2 3291 -e cmd Does anyone know how to list incoming connection attempts rather than accept one? ...
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1answer
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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2answers
717 views

ssh -R then expose the local port over HTTP?

Here's my scenario, I have two machines, A and B. A is behind a VPN, so B can't get to A. I have a web server: machine_a$ curl localhost:8088 "hello from machine_a" I have executed a remote SSH ...
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0answers
4k views

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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3answers
1k views

How to make netcat support ssl by combining openssl?

Original netcat doesn't support ssl. ncat from nmap project does. In linux, we can connect multiple commands with pipeline. Is it possible to combine netcat and openssl to create a ncat?
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2answers
4k views

How to download a URL from internet by netcat?

I can use netcat to transfer files between two computers. # Server nc -l -p 8080 < file # client nc 192.168.1.101 8080 > file Can I use netcat to download a URL from Internet like wget?
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1answer
252 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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2answers
8k views

Sending text file contents to server using netcat?

There is a daemon process listening on port 5144, which I cannot to modify. I want to use netcat to send the contents of a text file to the server, but this causes netcat to hang the terminal until I ...
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2answers
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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1answer
145 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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2answers
578 views

Nested Redirection in BASH

I have a scenario where I want to filter log files. To do this I am wanting to follow the last 10 lines or so of a log file and as new lines are read in, pipe them through an awk program and then ...
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738 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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1answer
776 views

How to pipe the output of a linux command back into the predecesssing command

The linux command nc -l 8090 | (read METHOD URI PROTOCOL ; echo "method: $METHOD" ; echo "path: $URI" ; echo "prot: $PROTOCOL") listens to port 8090 and when I type something like ...
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3answers
3k views

Use netcat as a proxy to log traffic

I want to use netcat as a proxy to log http requests and responses to files, then tail these to inspect traffic. Think wireshark. Tried the following where 'fifo' is a named pipe, 'in' and 'out' are ...
2
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1answer
959 views

Unix bidirectional pipe on commandline

I've been able to use this linux command to connect Netcat to a serial port: nc -l 80 <> /dev/ttyS0 I would like to be able to log this transaction. My backup plan is to use Wireshark to ...
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1answer
733 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 ...
7
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1answer
9k views

Why is “nc -l xxxx” not opening a port?

I'm trying to get netcat to listen on port 4444, but it doesn't seem to be working. I am checking to see if the port is open using nmap, but it doesn't pick it up and I can't figure out why. I have ...
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2k 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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3answers
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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1answer
2k 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 ...
14
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1answer
6k views

How can I force netcat to send my input immediately, not just on newlines?

How can I force netcat to send my input immediately, not just on newlines? I want to test an HTTP parser manually and check how it behaves when header lines are spread across multiple packets.
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3answers
5k views

How to get the WAN IP from a router using UPnP/SSDP

I'm trying to find a way to get my router to report back my WAN IP using UPnP/SSDP, but so far I have been unable to even get a list of UPnP supporting internet access devices on my network. Here's ...
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0answers
2k 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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1answer
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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2answers
752 views

How to set up a secure chat using netcat

I use netcat to chat in LAN. PC1 listen port 8080 $ nc -l -p 8080 PC2 connect to PC1:8080 $ nc 192.168.10.1 8080 Unfortunately, this is not secure. Anyone sniffing packets can intercept my ...
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1answer
845 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 ...
2
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1answer
3k views

bidirectional socat functionality with nc

This is question is somehow related to How is it called when listening(connecting) two sockets and exchanging data between them? In the test setup I have three terminal windows open I run in Term1: ...
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1answer
253 views

Can I use dd to clone two drives from two machines simultaneously?

To clarify, I have two machines: Machine1 and Machine2. Each machine has 2 disks (Machine1 has Disk1-1 and Disk1-2; simiarly, Machine2 has Disk2-1 and Disk2-2). Can I use 'dd' to clone Disk1-1 to ...
29
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3answers
22k views

Can the telnet or netcat clients communicate over SSL?

I would like to test client connections with IMAP over SSL, HTTPS, and other secure text-based Internet protocols over SSL/TLS, the same way I would using telnet or netcat if they were not tunneled ...
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1answer
350 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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1answer
205 views

Monitoring incoming requests on a web hosting server

I have a web hosting account with GoDaddy (its a Linux based hosting). Can I install applications like netcat to monitor all incoming requests to my website on a certain port? If not, is there any ...
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2answers
11k views

Netcat/socat behavior with piping and UDP?

I guess this is close to linux - Netcat stops listening for UDP traffic - Super User, but I thought I'd better ask anyways As far as versions of netcat I'm using Ubuntu 11.04 and the default netcat ...
4
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2answers
11k views

Linux built-in or open source program to join multicast group?

I'm using tcpdump to capture multicast packets and had to code up a custom program to join multicast feeds so tcpdump will "see" the packets. Just wondering if netcat or any other applications can ...
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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
145 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?