You want to test whether a machine is alive. Network and system
monitoring software often use the
ping program as
an indicator of availability.
Use the standard Net::Ping module:
use Net::Ping; $p = Net::Ping->new() or die "Can't create new ping object: $!\n"; print "$host is alive" if $p->ping($host); $p->close;
Testing whether a machine is up isn’t as easy as it sounds. It’s not only possible but it’s also unpleasantly common for machines to respond to the ping command and have no working services. It’s better to think of a ping as testing whether a machine is reachable, rather than whether the machine is doing its job. To check the latter, you must try to use its services (telnet, FTP, web, NFS, etc).
In the form shown in the Solution, Net::Ping attempts to connect to
the UDP echo port (port number 7) on the remote
machine, send a datagram, and receive the echoed response. The
machine is considered unreachable if it can’t connect, if the
reply datagram isn’t received, or if the reply differs from the
original datagram. The
ping method returns true if
the machine was reachable, false otherwise.
You can also ping using other protocols by passing the protocol name
new. Valid protocols are
tcp, udp, and
icmp (all lowercase). A TCP ping attempts to connect to the echo port (TCP port 7) on the remote machine, and returns true if the connection could be established, false otherwise (unlike UDP ping, no data is sent to be echoed). An ICMP ...