how to send udp packet to the DNS using netcat

piyara · 06-16-2010, 10:09 AM

Can anybody help me that how can i send udp packet to the DNS using netcat in opensuse.

anomie · 06-16-2010, 10:16 AM

For what purpose?

The nc(1) manpages have documentation on using UDP.

piyara · 06-16-2010, 12:16 PM

i have tried but it is not working.the command which i used is
netcat -uvv [host_name] [port_number]
e.g
netcat -uvv 8.8.8.8 53
annd then press enter. then i entered some text but it was stucked. when i pressed ctrl+c it was exit giving send 10 rcvd 0

anomie · 06-16-2010, 12:59 PM

Again, what is the purpose of this? You need to send a single UDP packet to the remote host? You need to ship data over UDP to the host? Or what..?

zidane_tribal · 06-16-2010, 01:39 PM

Quote:

Originally Posted by piyara

i have tried but it is not working.the command which i used is
netcat -uvv [host_name] [port_number]
e.g
netcat -uvv 8.8.8.8 53
annd then press enter. then i entered some text but it was stucked. when i pressed ctrl+c it was exit giving send 10 rcvd 0

curiouser and curiouser, why are you experimenting against googles dns servers? http://code.google.com/speed/public-dns/

whatever you are doing, i doubt you should be doing it with netcat and against a public dns server.

piyara · 06-16-2010, 02:43 PM

Thanx anomie for such immidiate responses. i have achieved the goal by this command
netcat -uvv [host_name] [port_number]

But now i want to calculate time difference between sending the packets and receiving the packets from the DNS. the problem is that after entering the above mentioned command, it waits for the input, and after the input response is shown by the dns. how can i take the difference of time????

anomie · 06-16-2010, 03:23 PM

One option is to observe packets with tcpdump(8) and then check timestamps.

Code:

# tcpdump -i eth0 udp port 53

Replace "eth0" with appropriate interface.

piyara · 06-16-2010, 03:51 PM

can i use "tcpdump" to monitor UDP packets in wireless network??