Commands tagged icmp (7)

  • this command will send a message to the socket 25 on host in tcp. works on udp and icmp understand only IP address, not hostname. on the other side (, you can listen to this socket and test if you receive the message. easy to diagnose a firewall problem or not.

    echo "foo" > /dev/tcp/
    mobidyc · 2009-09-12 16:48:05 3
  • 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"

    sudo -s "echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all"
    sliceoflinux · 2010-06-22 19:16:43 0
  • 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(('', 25), SocketServer.BaseRequestHandler).serve_forever()" Show Sample Output

    echo foo | netcat 25
    pykler · 2009-09-13 01:33:02 0
  • Change the IP address from 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. Show Sample Output

    nmap -sT -PN -vv <target ip>
    Richie086 · 2011-07-22 02:37:19 0
  • Quick OneLiner to sniff for ICMP traffic, proof of concept socket code. Needs root privs to run. Show Sample Output

    echo "exec(\"import socket, os\nwhile True:\n\tprint (socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_ICMP)).recvfrom(65565)\")" | sudo python
    justinf · 2015-05-24 08:19:55 0
  • IMPORTANT: You need Windows PowerShell to run this command - in your Windows Command Prompt, type powershell Uses sajb to start a PowerShell background job that pings an IP host every 10 seconds. Any changes in the host's Up/Down state is time-stamped and logged to a file. Date/time stamps are logged in two formats: Unix and human-readable. A while(1) loop repeats the test every 10 seconds by using the sleep command. See the Sample Output for more detail. I use this command to log Up/Down events of my Motorola SB6141 cable modem ( To end the logging, close the PowerShell window or use the "exit" command. Show Sample Output

    sajb {$ip="";$old=0;while(1){$up=test-connection -quiet -count 1 $ip;if($up-ne$old){$s=(date -u %s).split('.')[0]+' '+(date -f s).replace('T',' ')+' '+$ip+' '+$(if($up){'Up'}else{'Down'});echo $s|out-file -a $home\ping.txt;$old=$up}sleep 10}}
    omap7777 · 2015-12-28 20:33:08 0
  • 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. Show Sample Output

    echo foo | ncat [ip address] [port]
    dragonauta · 2012-10-26 10:53:47 0

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