http://www.perlmonks.org?node_id=1140813


in reply to Ping and Linux firewall

By default Net::Ping does a tcp ping. Normal OS pings are usually ICMP. You could try allowing inbound port number 7 to make the TCP Net::Ping work or
$p = Net::Ping->new("icmp");
to make your Net::Ping use ICMP protocol.