Questions tagged [netcat]
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.
218 questions
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Clone ntfs partition (with linux) over network
I have two computers running with Linux, they each have a disk attached with a ntfs partion on it (/dev/sda3) -- one contains a Win10 install, the other is empty. What I want to do is to clone the ...
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How to check if current user can listen on a privileged port?
Before starting a Java program I would like to run a script to check if the process will be able to listen on port 443. This script should try to listen to the port, if it is able to then close the ...
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Unable to Send TCP Packet via hping3 to Netcat Listener without RST Response
I am working on a project where I need to send a TCP packet containing my surname via hping3 from a client (Kali Linux) to a server (Ubuntu) where I have a netcat listener running. The goal is to send ...
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Odd behavior of Netcat
I'm trying to debug connection issues within my home network. To do that, I'm using Netcat to figure out if two machines can talk to each other over UDP on a specific port.
On the reveiver's end, I ...
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nc and socat parallel listening the same TCP port
Some device sending into 1234/TCP Linux machine some data.
Now I using nc and socat command for handle the data and process it but when using 1st command 2nd cannot be executed and vice-versa.
nohup ...
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Can't send UDP packet via DDNS domain name
I'm trying to set up WireGuard and am running into multiple issues. To debug, I'm using WireShark to verify if any packets make it to my server, which runs on a laptop in a private network behind a ...
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What format does a Postfix Milter use?
I am attempting to write a custom miller for postfix , but am not sure what format I need to use before I begin writing my logic.
So far, I have postfix sending mail to a miller with:
...
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Multiple netcat connections in old version of linux
I'm running a 32-bits old version of CentOS in a offline LAN network. I'd like to setup communication between all hosts, pretty much like nc -l 5555 + nc <ip1> 5555 works. Well, I'm aware that ...
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Ncat inside WSL2 not behaving correctly
I have an instance of kali linux running in WSL2 on Windows 11. It is configured to use mirrored networking mode, if that is relevant. Typically, if one were to start listening on 127.0.0.1 on any ...
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Double SSH then execute NC using Batch file and Plink
Good morning,
I need to execute a netcat command and get the output to do elaboration on my local PC (windows). I just need the "connection good/bad"
Now I use PuTTY using the following step
...
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Why does netcat -v send extra X packets?
I'm using netcat 1.218 on Ubuntu 22.04 to generate test syslog packets, and I noticed an odd behavior I can't explain. When I use the -v flag, netcat sends 2 additional packets containing the letter ...
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How to switch between sessions in NetCat
I have a nc in listen mode
nc -klvmp 12345 --max-conns 3
I create 3 sessions. At the end I want to be able to switch on the server side between client's sessions. Or work in 1 and then close it and ...
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Why can I `curl localhost:<port>` but can't `curl <my IP>:<port>`?
I start by retrieving my IP address by running ifconfig | grep -B7 "status: active". Then, I listen on port 12345 by running nc -l 12345.
Observations:
curl localhost:12345 works
curl <...
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Is it safe to expose a port opened from netcat?
I'm planning to open a port from a device inside my LAN to the internet with the command:
nc -kl 9999 > /dev/null
The idea is just to know if that specific device is powered on whenever I want to ...
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What possibly a Mac prohibit remote connection?
With my company Mac, I can't connect to one of my company's server:ppppp.
The problem is all my colleagues can connect to the server:ppppp.
All environments are same.
Connect VPN
all works including ...
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Pipe Python command output to netcat without sending an EOF
I have access to an external netcat server to which I am trying to send a large input. I am currently trying to do so with this command:
python -c 'print("a" * (50000-64))' | nc www.host.net ...
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How to prevent change of bytes when transferring file with nc?
If you open a port on a listening host and send bytes with nc to this port, the hash of the source and destination file might not be the same. Why is that and can it be prevented?
Here are the ...
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socat TCP server bidirectional using sleep, non-interactive client returns without response. Server reports: I/O error
I have the following TCP server:
socat TCP-LISTEN:10000,fork,reuseaddr SYSTEM:'read -r msg && sleep 3 && echo "OK"'
When I execute (interactive mode):
socat - TCP:localhost:...
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Using netcat / ncat to test the Hole Punching paradigm / technique
Being in need to revalidate rationale behind internal workings of protocols of my own I decided to play around with netcat to simulate what's to be going on under the hood.
The Aim
Is to simulate the ...
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why does netcat work(to scan) faster in local host in virtual box but not for remote server?
I am using netcat to scan the ip of metasploitable2 from my kali machine in virtual box.netcat is very much faster to scan an ip of a local machine in virtual box. But when I am trying to scan a ...
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Netcat connection not working both ways (Mac-Kali), connection refused
I was following this website in order to establish a netcat connection. I have a mac and a kali virtual machine. If from my mac I type nc -lv 1234 and from kali I type nc ip.of.my.mac 1234 then the ...
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Why is netcat not running like it should on my macOS?
I tried running nc -lnvp 1234 > filename.log on my macOS today and it returned this error saying I need to specify a port number, while I specified the port number on my command.
This command ...
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Could someone execute commands on my netcat server/listener?
TLDR
Someone has connected to my netcat server and tried to execute a command. Is it possible they have done any harm to me/my computer/my network?
Detailed story
I've been learning about networking ...
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How to use netcat on Mac?
I start the app with sockets on Mac and returns following:
kukodajanos@Kukodas-MacBook-Pro niots % swift run
Building for debugging...
[2/2] Emitting module niots
Build complete! (0.30s)
Server ...
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Log IP address using netcat
How to log IP address every time which is connected to the port, I'm using nc to listen and tee to append in a log file
netcat -lkv -W2 -p 4000 | tee -a /tmp/netcat.log
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Linux Remove Previous nc Directive
I need to use nc -lp4 5432 --allow 192.168.1.24 but I have a previous nc directive that only has it listening on localhost. It throws an error when I try overwriting it:
$ nc -lp4 5432 --allow 192....
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Open shells with ncat on wan target
I created an azure VM and I configured a ngrok server to make my localhost accessible from internet and I put a VPN to VM in order to simulate a wan attack.
What I want is to set a TCP connection to ...
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How to create a serial over LAN server under Linux, using virtual ports
I am able to connect to serial over LAN devices (like USRIOT-TCP-232-302), as client, from my linux server, using socat and it works pretty well.
I now would like to have devices connecting to the ...
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Sending PJlink commands with netcat
I have a projector that I want to control over TCP using a protocol called "PJlink", but I can't manage to get it working. I'm currently trying to do this through Windows Terminal in WSL ...
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Use netcat to send UDP packets out 1 ethernet port and into another on the same server
I am trying to sanity check a network device and want to use netcat to send upd traffic out a specific ethernet port (eth0 for example) and receive that packet on a different port on the same system (...
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When sending email to Gmail address from netcat or openssl s_client, why do I get "Username and Password not accepted", despite correct credentials
My goal was to send an email to a gmail address, like [email protected] from a commandline tool such as netcat or telnet etc.
WHAT I TRIED:
I first tried netcat.
nc -C smtp.gmail.com 587
220 smtp.gmail....
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Is it possible to make Netcat behave exactly like Telnet?
Is it possible to make Netcat behave exactly like Telnet?
The "-t" option doesn't seem to quite do it.
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Simulate "Enter" keypress after successfully making connection using Netcat on Raspberry Pi
I have an issue with using Netcat on Raspberry Pi terminal to output data after making a connection. The issue is that when I run this command, after it is succeeded, 5 seconds pass, and the ...
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Trying to start nc listener via torify?
Trying to start nc listener via torify:
torify nc -lvnp 4444
get response: local listen fuxored: Operation not permitted
I then tried to add: -q -1 and got same response?
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nc Won't Listen on a Port on CentOs6
I'm playing with nc for the file transfer function. On a CentOS6 machine, If I put nc on the listening mode, it returns a help message instead.
It seems nc with older visions needs different ...
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how to do netcat in a terminal
i have a program that is like a terminal that i want always on, how do i put it in a port through netcat so when i connect to that port i can write in the terminal and when i exit, the program doesn't ...
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Netcat or similar: Dockerized general purpose TCP/IP port proxy/gateway (for any service: mysql, ssh, dns, etc)
Context
We manage a radio station with 35+ workplaces for journalists. All them using a desktop application, connecting to a MySQL exposing 3306 at some internal IP address.
There are also other ...
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difference between nc and telnet using smtp service as an example
I can use both nc and telnet to connect to port 25.
$ nc 192.168.1.120 25
220 localhost ESMTP Exim 4.68 Tue, 29 Dec 2020 06:07:27 +0000
$ telnet 192.168.1.120 25
Trying 192.168.1.120...
Connected to ...
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Redirect arecord output and send it with netcat
I am trying to redirect sound from a microphone from one computer to another in my local network. I did following to achieve that
In one terminal:
arecord -t raw -c 2 -f S16_LE -r 48000 | nc -u #...
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How to netcat to multiple ports
I'am using a raspberry and i need 2 local streams. This is what i've tried:
Attempt
raspivid <some options> -o - | tee nc localhost 5100 | nc localhost 5000
Question
I can receive the output on ...
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monitor PID and respawn processes in bash script (simulatord, nc, ping)
For a student environment, I have a simple bash script that runs upon boot up on Ubuntu 18.04 (@reboot in crontab -e).
It runs ok (java file starts, netcat starts, pings, and all PIDs are viewable via ...
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Connection refused, but port is open
My Idea was to make netcat-Connection between two devices in different LAN; Now I looked in settings of WiFi-Router and created a port forwarding; port 4004 of router should now be able to connect me ...
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Bypass Linux password login with netcat or ssh or telnet
How can you bypass a password login with nc or ssh? I type 'nc IP-address 13880' and it gives me the login form I need to bypass. Can anyone give me any tips?
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Use netcat to listen on a port and send output from a command when a client connects
I have a Raspberry Pi (Debian Linux) connected to my LAN that can read data from some connected devices and output it to STDOUT.
Let's say the program is run on "Server" and I want to serve the ...
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How to transfer files between two hosts through a bastion using netcat and pigz
I have to regularly transfer the contents of folders containing a lot of small files with a volume of around 10GB from one server to another. Before I used the command bellow which did the job very ...
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Scan open port with netcat
I'm just wrapping my head around the utility netcat. So for test purpose I install Apache on my Linux OS and verified Apache runs by accessing the localhost url in my browser.
I want to test if the ...
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linux nc (netcat) UDP Connection refused
I faced with some strange nc behavior. It works well with TCP when on one host I do:
nc -tlp 31337
and on the other one:
nc 14.0.0.1 31337
So there can be some data exchange.
But when I do:
nc -...
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Netcat listening on Debian Security advice please nc -(dknl)
I would be very grateful for some help:
This is with regards to a Netcat based script running on a Debian based distribution, specifically the Proxmox hypervisor (see here if unknown https://en....
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SSH'ing through a proxy with CentOS 8
I'm using CentOS 8, and I'm trying to SSH from behind a firewall through a (HTTP but also somehow SOCKS) proxy.
I've read this answer, which suggests using nc -X - but my nc doesn't support that. I'...
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Install both gnu-netcat and openbsd-netcat simultaneously on Arch Linux
They are in conflict when I try to install them conveniently. How can I have both of them at the same time?
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