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Commands tagged socket

Terminal - Commands tagged socket - 6 results

nc -l <port-number>

2013-03-20 15:25:57

User: cybertoast

Tags: networking firewall socket port listen

-1

Up
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Listen on an arbitrary port

Simple way to test if a port is available to the public. Run this command on the "server" and run a `telnet host-ip port-number` on the client. Test by sending strings to the server, which will be displayed in the server terminal.

Comments (2) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate

echo foo | ncat [ip address] [port]

2012-10-26 10:53:47

User: dragonauta

Functions: echo

Tags: Network udp tcp icmp protocol socket

-1

Up
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send echo to socket network

you can use a pair of commands to test firewalls.

1st launch this command at destination machine

ncat -l [-u] [port] | cat

then use this command at source machine to test remote port

echo foo | ncat [-u] [ip address] [port]

First command will listen at specified port.

It will listen TCP. If you use -u option will listen UDP.

Second command will send "foo" through ncat and will reach defined IP and port.

for p in {1..1023}; do(echo >/dev/tcp/localhost/$p) >/dev/null 2>&1 && echo "$p open"; done

2010-04-26 18:09:22

User: benyounes

Functions: echo

Tags: scanner socket

Up
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Simplest port scanner

Very handy way to perform a host scan if you don't have nmap,ncat,nc ...or other tools installed locally.

When executing a command on a /dev/tcp/$host/$port pseudo-device file, Bash opens a TCP connection to the associated socket and UDP connection when using /dev/udp/$host/$port.A simlpe way to get servers banner is to run this command "cat < /dev/tcp/localhost/25" , here you will get mail server's banner.

NOTE: Bash, as packaged for Debian, does not support using the /dev/tcp and /dev/udp pseudo-device it's not enabled by default Because bash in Debian is compiled with ?disable-net-redirections.

python -c 'import socket; s = socket.socket(socket.AF_INET, socket.SOCK_STREAM); s.connect(("<hostname>", <port>)); print s.getsockname()[0] ; s.close() ;' 2> /dev/null

2009-10-13 16:21:15

User: angleto

Functions: python

Tags: python networking tcp socket

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retrieve the source address used to contact a given host

on multihomed hosts, connected to several networks, could be usefull to know the source address (local ip address) used to reach the target host, this command does not require root priviledges.

The command use a TCP socket, if there is any error the command return an empty string, elsewhere return a valid ip address.

echo foo | netcat 192.168.1.2 25

2009-09-13 01:33:02

User: pykler

Functions: echo

Tags: Network udp tcp icmp protocol socket

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send echo to socket network

Using netcat, usuallly installed on debian/ubuntu.

Also to test against a sample server the following two commands may help

echo got milk? | netcat -l -p 25

python -c "import SocketServer; SocketServer.BaseRequestHandler.handle = lambda self: self.request.send('got milk?\n'); SocketServer.TCPServer(('0.0.0.0', 25), SocketServer.BaseRequestHandler).serve_forever()"

echo "foo" > /dev/tcp/192.168.1.2/25

2009-09-12 16:48:05

User: mobidyc

Functions: echo

Tags: Network udp tcp icmp protocol socket

Up
Down

send echo to socket network

this command will send a message to the socket 25 on host 192.168.1.2 in tcp.

works on udp and icmp

understand only IP address, not hostname.

on the other side (192.168.1.2), you can listen to this socket and test if you receive the message.

easy to diagnose a firewall problem or not.

Comments (3) | Add to favourites | Report as malicious | Submit alternative | Report as a duplicate