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#!/usr/bin/perl -w
# Perl version of check_dns plugin which calls DNS directly instead of
# relying on nslookup (which has bugs)
#
# Copyright 2000, virCIO, LLP
#
# $Log$
# Revision 1.1 2002/02/28 06:43:00 egalstad
# Initial revision
#
# Revision 1.1 2000/08/03 20:41:12 karldebisschop
# rename to avoid conflict when installing
#
# Revision 1.1 2000/08/03 19:27:08 karldebisschop
# use Net::DNS to check name server
#
# Revision 1.1 2000/07/20 19:09:13 cwg
# All the pieces needed to use my version of check_dns.
#
use Getopt::Long;
use Net::DNS;
Getopt::Long::Configure(`bundling`);
GetOptions("V" => $opt_V, "version" => $opt_V,
"h" => $opt_h, "help" => $opt_h,
"t=i" => $opt_t, "timeout=i" => $opt_t,
"s=s" => $opt_s, "server=s" => $opt_s,
"H=s" => $opt_H, "hostname=s" => $opt_H);
# -h means display verbose help screen
if($opt_h){ print_help(); exit 0; }
# -V means display version number
if ($opt_V) { print_version(); exit 0; }
# -H means host name
$opt_H = shift unless ($opt_H);
unless ($opt_H) { print_usage(); exit -1; }
if ($opt_H &&
$opt_H =~ m/^([0-9]+.[0-9]+.[0-9]+.[0-9]+|[a-zA-Z][-a-zA-Z0]+(.[a-zA-Z][-a-zA-Z0]+)*)$/)
{
$host = $1;
} else {
print "$opt_H is not a valid host name";
exit -1;
}
# -s means server name
$opt_s = shift unless ($opt_s);
if ($opt_s) {
if ($opt_s =~ m/^([0-9]+.[0-9]+.[0-9]+.[0-9]+|[a-zA-Z][-a-zA-Z0]+(.[a-zA-Z][-a-zA-Z0]+)*)$/)
{
$server = $1;
} else {
print "$opt_s is not a valid host name";
exit -1;
}
}
# -t means timeout
my $timeout = 10 unless ($opt_t);
my $res = new Net::DNS::Resolver;
#$res->debug(1);
if ($server) {
$res->nameservers($server);
}
$res->tcp_timeout($timeout);
$SIG{ALRM} = &catch_alarm;
alarm($timeout);
$query = $res->query($host);
if ($query) {
my @answer = $query->answer;
if (@answer) {
print join(`/`, map {
$_->type . ` ` . $_->rdatastr;
} @answer);
exit 0;
} else {
print "empty answer";
exit 2;
}
}
else {
print "query failed: ", $res->errorstring, "";
exit 2;
}
sub catch_alarm {
print "query timed out";
exit 2;
}
sub print_version () {
my $arg0 = $0;
chomp $arg0;
print "$arg0 version 0.1";
}
sub print_help() {
print_version();
print "";
print "Check if a nameserver can resolve a given hostname.";
print "";
print_usage();
print "";
print "-H, --hostname=HOST";
print " The name or address you want to query";
print "-s, --server=HOST";
print " Optional DNS server you want to use for the lookup";
print "-t, --timeout=INTEGER";
print " Seconds before connection times out (default: 10)";
print "-h, --help";
print " Print detailed help";
print "-V, --version";
print " Print version numbers and license information";
}
sub print_usage () {
my $arg0 = $0;
chomp $arg0;
print "$arg0 check_dns -H host [-s server] [-t timeout]";
print "$arg0 [-h | --help]";
print "$arg0 [-V | --version]";
}
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