Revision as of 00:18, 7 August 2021

netcat is a tool for using and testing TCP.

NOTE:

netcat has been superceeded by ss

Install

pacman -S openbsd-netcat

nc -vz    x.x.x.x 80                      # ipv4 confirm port 80 open
nc -6 -vz xxxx:xxxx:xxx:xx::xxx::xxxx 80  # ipv6 confirm port 80 open

nc \
  -u  # send udp packets \
  -v  # verbose \
  -z  # check if reachable \

nc -l -p 6001                     # Listen to port 6001 on localhost

echo "hello" | nc 127.0.0.1 6001  # Send test 'hello' to port 6001 on localhost

@@ Line 1: / Line 1: @@
-NetCat is a very useul tool for sending/receiving messages over TCP.
+netcat is a tool for using and testing TCP.
-I use it ''almost-daily'' to test daemons, servers, connections, etc.
-I believe technically it is slowly being replaced by '''ss''', which I still
-need to read up on.
-It's syntax varies slightly from platform to platform, but it's man-page is
+{{ NOTE |
-very comprehensive and helpful.
+netcat has been superceeded by [[ss]] }}
+= Install =
+<blockquote>
+<syntaxhighlight lang="bash">
+pacman -S openbsd-netcat
+</syntaxhighlight>
+</blockquote><!-- Install -->
-<source lang="bash">
+= Usage =
+<blockquote>
+<syntaxhighlight lang="bash">
+nc -vz    x.x.x.x 80                      # ipv4 confirm port 80 open
+nc -6 -vz xxxx:xxxx:xxx:xx::xxx::xxxx 80  # ipv6 confirm port 80 open
+</syntaxhighlight>
+<syntaxhighlight lang="bash">
 nc \
    -u  # send udp packets \
    -v  # verbose \
    -z  # check if reachable \
-</source>
+</syntaxhighlight>
-<source lang="bash">
+<syntaxhighlight lang="bash">
 nc -l -p 6001                     # Listen to port 6001 on localhost
 echo "hello" | nc 127.0.0.1 6001  # Send test 'hello' to port 6001 on localhost
-</source>
+</syntaxhighlight>
+</blockquote><!-- Usage -->
-<source lang="bash">
-nc -z domain.com 443   # check errorcode to see if connection was possible
-</source>