By default Net::Ping uses a different method of determining a host's status (TCP echo) than the 'ping' utility (ICMP echo) because doing ICMP echo on unix systems requires root privileges to open a so-called "raw socket".

You can however make Net::Ping use the external ping utility via the Net::Ping::External module if you want to do ICMP echo without running your script as root.

See the documentation of Net::Ping (note that CPAN has a more recent Net::Ping than the one included with perl 5.8.0)

•Update: It's still odd however that it doesn't work at all.. even when a TCP echo service isn't running on a host (these days it almost never is) it should still get a "connection refused" which it would interpret as "the host is alive since it can refuse the connection".

Is it possible there's a firewall in the way that blocks tcp port 7 (echo) ? Try setting the port to 80 by doing: 

$p->{port_num} = 80;

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In reply to Re: Unexpected results from ping by xmath
in thread Unexpected results from ping by GreyOwl

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