#!/usr/bin/perl
=begin metadata
Name: ping
Description: probe for network hosts
Author: Nick Ing-Simmons, nick@ni-s.u-net.com
License: perl
=end metadata
=cut
use strict;
use Getopt::Std;
use Socket;
use Net::Ping;
my %opt;
getopts('nI:',\%opt);
die "Usage: $0 host [timeout]\n" unless @ARGV;
my $host = shift;
my $timeout = (@ARGV) ? shift : 20;
my $a = gethostbyname($host);
if ( $a ) {
if ( $opt{'n'} ) {
my $name = inet_ntoa($a);
$host = $name if ($name);
} else {
my $name = gethostbyaddr($a,PF_INET);
$host = $name if ($name);
}
my $handle = Net::Ping->new($> ? 'udp' : 'icmp', $timeout);
if ( $handle->ping($host) ) {
warn "$host is alive\n";
} else {
die "No answer from $host";
}
} else {
die "Unknown host $host\n";
}
__END__
=head1 NAME
ping - probe for network hosts
=head1 SYNOPSIS
ping [-n] hostname [ timeout ]
=head1 DESCRIPTION
C<ping> looks up I<hostname> and then attempts to contact it via the network.
If the effective userid permits an ICMP (Internet Control Message Protocol)
ECHO_REQUEST packet is sent, otherwise and attempt is made to connect to
the echo port using UDP protocol.
A I<timeout> may be specified in seconds. The default is 20 seconds.
If C<-n> option is specified then the address of I<hostname> is reported
as numbers.
=head1 AUTHOR
Nick Ing-Simmons <nick@ni-s.u-net.com>
=cut