Questions tagged [nc]
`nc` is the "network `cat`" program, connecting Unix pipe I/O to TCP and UDP sockets.
21
questions with no upvoted or accepted answers
2
votes
0
answers
649
views
Is there any way to send request via authenticated proxy in OpenBSD netcat (nc)?
I am using following command using the nc to connect to my server via proxy (localhost:8080). But this proxy is authenticated. I am not sure how to pass the auth details. Pls. note this is older ...
- 121
2
votes
2
answers
3k
views
How do I write a simple request/response tcp server using `nc`?
I’m trying to write a request/response TCP server to handle a small number of very simple commands. I'm using a shell script to be as portable as possible, avoiding compilation or requiring specific ...
- 121
2
votes
0
answers
1k
views
netcat -s switch does not work or do anything at all
I have a computer with a NIC with two ports and a switch between them, and I'm trying to send data from one port to the other using netcat. I thought I could simply specify the source address (i.e. ...
- 129
2
votes
1
answer
2k
views
How to decrypt Cryptcat (twofish) data?
I have some packets that are encrypted with Cryptcat tool and I want to decrypt them. I have the encryption password. I tried to use netcat with cryptcat, but every time I'm connecting from netcat to ...
1
vote
0
answers
601
views
Basic webserver supporting post+get (using curl and netcat)
Sorry if the question's title isn't clear about the objective of this question.
I was able to make a respond-only webserver using Bash only; when it gets a curl post request, it returns results no ...
1
vote
0
answers
1k
views
nc -lvnp (port) Non-responsive w/ PHP Reverse Shell til closed
I am currently working on Machine's on HackTheBox. I've used nc -lvnp (port) quite a bit and i've never ran into this issue:
$nc -lvnp 4444
listening on [any] 4444 ....
connect to [my IP] from (...
- 11
1
vote
0
answers
687
views
How to `nc -l 1234 | bash` but send response back to connecter
I have a basic netcat listener on my network that uses this command: nc -l 1234 | bash. This command runs everything it receives in nc into BASh. It works, however, only the listener can see the ...
- 253
0
votes
1
answer
50
views
Redirect command options to a file
From the following nc command,i would like to redirect source-server.fqdn name to the output file. By default nc command is not returning the source-server.fqdn in the output.
nc -zv -s source-server....
- 1
0
votes
0
answers
32
views
Why do udp requests fail temporarily
I've a UDP web server, which bound to the port 10000. I just deployed it on the server 172.20.0.10. Then I tried to scan the port nc -v -z -w2 -u 172.20.0.10 10000, it seems that everyting is OK. The ...
- 3,301
0
votes
0
answers
77
views
finger daemon / nc fowarding error
For an assignment I'm trying to properly send a buffer overflow exploit with ncat in order gain root access on a vulnerable machine set up by the professor. I feel I created my egg right but I keep ...
0
votes
1
answer
73
views
Weird behaviour of bash in Kali Terminal (Qt I think) - piping to nc ends with awaiting input forever
I've been trying to pipe bytecode to netcat (nc) like this:
python3 -c "import sys;bof='a'*16;bof2='a'*8;sys.stdout.buffer.write(bof.encode('ascii')+b'\xef\xbe\xad\xde'+bof2.encode('ascii')+b'\...
- 1,296
0
votes
2
answers
792
views
netcat in systemd service resets
I am using netcat to connect to a server over TCP and continuously pipe the data received to file.
nc 10.0.2.2 3456 > file.data
When running this from terminal or a script it stays connected
I want ...
- 1
0
votes
0
answers
117
views
Userspace solution to use store data and create a UDP server
I'm trying to come up with a good way manage an intermittently connected device that I'm using for a research project. It's a sensor that goes in and out of the water. While under water, of course, ...
- 111
0
votes
1
answer
120
views
Add reponse to the Listening port created with nc -l localhost <some port>
How can I setup a functionality to a listening port created using the nc -l command. I want my server to respond with a pass after connection
- 143
0
votes
1
answer
1k
views
netcat / nc / telnet perform math on received data then output
I am not an expert on bash so sorry in advance. For my high school CTF competition, I have to read in 3 numbers, perform some arithmetic on them, then output the value back to the server.
In ...
0
votes
1
answer
451
views
nc: run command upon connection
When doing CTFs, I often run nc -lnvp $PORT and do something else while waiting for a connection. I want to be alerted when said connection is established and I get a shell. Since nc is not terminated ...
0
votes
1
answer
336
views
Can't ncat some ports after opening them in the router and with firewall-cmd
I want to open some ports, both UDP and TCP, on a Fedora 32 server.
First, I've opened them on the router and then restarted the router:
Then, I've opened them in firewalld:
sudo firewall-cmd --...
- 119
0
votes
0
answers
1k
views
netcat is timing out before timeout has reached
I am trying to test a port on a remote machine. The connection is over satellite, so latency is quite high. I am testing with NC with the -w option to set the timeout. Ex: nc -w 300 address port ...
- 3
0
votes
1
answer
347
views
VPN Clients only can connect to other machines after ping
I have a weird problem. I have an OpenVPN server up and running. When my VPN clients (10.0.0.x) try to connect to another machines (192.168.0.x), they fail (I tried netcat, telnet and SIP). If I ...
0
votes
1
answer
734
views
How can a client talk to another client using unix domain sockets?
Using bash we might have something like this with netcat:
nc -lk -U /my/fifo | while read line; do
# line => {"client_id":123}
done;
clients send data like this:
echo '{"client_id":123,"data":...
- 10k
-1
votes
1
answer
2k
views
How to make nc listen for remote connections
I'm trying to listen for a remote connection but nc keeps giving me this error:
Error: Couldn't setup listening socket (err=-3)
This is the command I used:
nc -lvnp port_number -s my_public_ip
