quick ping

APRESTOUS · 05-02-2006, 10:49 AM

Maybe it would fit in Newbie forum...

When I ping a host and host is available - I receive an answer within no time.
When the host is not available - it lasts about 5 second before I get an answer.
I need to scan my LAN to know who is online. So 5 seconds per host is too much.
Is there some quick and durty way to do it?

carambar · 05-02-2006, 10:55 AM

I seem to remember that you can use the -w parameter with the ping command to set a timeout value (in milliseconds), so you might want to try using that.

sarin · 05-02-2006, 11:00 AM

Try ping -b <bcast> for a few seconds and then filter the data. This may not always give you all the hosts. Also you may try -W option (ping -c 1 -W 1 <ip>).

APRESTOUS · 05-02-2006, 11:13 AM

Quote:

Originally Posted by carambar

I seem to remember that you can use the -w parameter with the ping command to set a timeout value (in milliseconds), so you might want to try using that.

Thank you, very nice. I use -w 1 and it is decreased to 1 second. Is 1 second the minimum?
When I try to use -w 0.1 - it doesn't work.

marozsas · 05-02-2006, 11:22 AM

Quote:

Originally Posted by APRESTOUS

I need to scan my LAN to know who is online. So 5 seconds per host is too much.

Try fping. It is good to pinging several hosts with a single command and it has controls to limit the number of pings in each hosts and time (e.g. fping -B 1 -c 1)

APRESTOUS · 05-02-2006, 11:54 AM

Thanks! fping looks the best solution.
ALready installed and testing :-))

APRESTOUS · 05-03-2006, 02:29 AM

Impressions:

It begins very fast. Run through all hosts. But then it begins the second run and it takes a lot more time.
And I do not see how I can avoid it.

I use now fping -a -B 1 -r 1 -g 192.168.1.1 192.168.1.90 -s -t 1

marozsas · 05-03-2006, 06:50 AM

I am sorry, but here, I replay your command changing only the net range, and I can't tell there is a significative difference between consecutive runs.

Code:

# time fping -a -B 1 -r 1 -g 192.168.155.150 192.168.155.200 -s -t 1
--output cuted ---
      51 targets
       1 alive
      50 unreachable
       0 unknown addresses

     100 timeouts (waiting for response)
     101 ICMP Echos sent
       1 ICMP Echo Replies received
      84 other ICMP received

 0.52 ms (min round trip time)
 0.52 ms (avg round trip time)
 0.52 ms (max round trip time)
        4.489 sec (elapsed real time)


real    0m4.492s
user    0m0.000s
sys     0m0.000s
# time fping -a -B 1 -r 1 -g 192.168.155.150 192.168.155.200 -s -t 1
--output cuted ---
      51 targets
       1 alive
      50 unreachable
       0 unknown addresses

     100 timeouts (waiting for response)
     101 ICMP Echos sent
       1 ICMP Echo Replies received
      80 other ICMP received

 0.20 ms (min round trip time)
 0.20 ms (avg round trip time)
 0.20 ms (max round trip time)
        4.397 sec (elapsed real time)

real    0m4.403s
user    0m0.000s
sys     0m0.000s
# time fping -a -B 1 -r 1 -g 192.168.155.150 192.168.155.200 -s -t 1
--output cuted ---
      51 targets
       1 alive
      50 unreachable
       0 unknown addresses

     100 timeouts (waiting for response)
     101 ICMP Echos sent
       1 ICMP Echo Replies received
      84 other ICMP received

 0.59 ms (min round trip time)
 0.59 ms (avg round trip time)
 0.59 ms (max round trip time)
        4.487 sec (elapsed real time)


real    0m4.492s
user    0m0.004s
sys     0m0.000s
#