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Commands tagged icmp from sorted by
Terminal - Commands tagged icmp - 5 results
echo foo | ncat [ip address] [port]
2012-10-26 10:53:47
User: dragonauta
Functions: echo
-1

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.

nmap -sT -PN -vv <target ip>
2011-07-22 02:37:19
User: Richie086
0

Change the IP address from 127.0.0.1 to the target machines ip address. Even if the target has ICMP (ping) blocked, it will show you what ports are open on the target. Very handy for situations where you know the target is up and online but wont respond to pings.

sudo -s "echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all"
2010-06-22 19:16:43
User: sliceoflinux
Functions: sudo
Tags: ping icmp
6

It really disables all ICMP responses not only the ping one.

If you want to enable it you can use:

sudo -s "echo 0 > /proc/sys/net/ipv4/icmp_echo_ignore_all"
echo foo | netcat 192.168.1.2 25
2009-09-13 01:33:02
User: pykler
Functions: echo
2

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
23

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.