At 09:19 AM 2/22/02 +0000, Lanceo wrote:
>Hi,
>
>I am having difficulty getting the Net::Ping module to work properly. I am
>using ActivePerl 5.6.1.631 on a win32 platform. I can ping a server in a
>dos prompt ok, but when I try to get the Perl Net::Ping to work it always
>returns a failure. It seems to ponder over pinging the host for a couple of
>seconds, and then return a zero as a result, which means that it could not
>reach the host, if my interpretation of the docs is correct.
>
>Here is the snippet in question:
>
> my ($pingThing, $host, $pingResult);
> $host = 'www.google.com';
> $pingThing = Net::Ping->new("tcp", 1);
> $pingResult = $pingThing->ping($host);
I've seen this sooo many times. The answer: www.google.com responds to
ICMP ping packets (which are what the ping program sends) but has chosen
(or some router in between has chosen) not to respond to TCP ping packets
(which are what Net::Ping sends). Don't need to be on DOS to find this
out, here's Linux:
$ ping www.google.com
PING www.google.com (216.239.51.100) from 24.67.203.181 : 56(84) bytes of data.
64 bytes from www.google.com (216.239.51.100): icmp_seq=0 ttl=52 time=119.7 ms
64 bytes from www.google.com (216.239.51.100): icmp_seq=1 ttl=52 time=116.1 ms
^C
$ perl -MNet::Ping -le 'print "#5 is alive" if
Net::Ping->new->ping("www.google.com")'
$
Okay, so let's use ICMP packets. On Unix, we have to be root:
$ su
Password:
# perl -MNet::Ping -le 'print "#5 is alive" if
Net::Ping->new("icmp")->ping("www.google.com")'
#5 is alive
But on DOS, you don't ("security? what's that"):
C:\WINDOWS\Desktop>perl -MNet::Ping -le "print qq(#5 is alive) if
Net::Ping->new(qq(icmp))->ping(qq(www.google.com))"
#5 is alive
--
Peter Scott
Pacific Systems Design Technologies
http://www.perldebugged.com
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