#!/usr/bin/perl -wT

# ckdns.perl
# confirm dynamic DNS update
# ToDo:
#     reverse lookup (just for kicks)
#     CGI form for non-default lookup


use Net::DNS;
use Time::localtime;
use strict;
use vars qw( $default $name  $time  $pid  @ppp
             $pppip @mx  $line  $nameserver @ARGV
             $nameresolution  $res $query
             $rr  $queryNS $resNS  $resMX
           );


my $default = 'myddnshost.dom';
my $ns1  = 'dns.some.dom';
my $ns2  = 'dns.someother.dom';
my $ns3  = 'dns.yetanother.dom';
my $ns4  = 'dns.andanother.dom';
    # using nameservers' address instead of name
    # might be a bit better, but hostname
    # provides more informative output.


select ((select(STDOUT), $|=1) [0]);
    # hot STDOUT fixes sequence problem - TPJ #11
$ENV { 'PATH' } = '';
    # unTaint backticks by clearing path


    ## REPORT HEADER ##
my $tm   = localtime;
printf "\n%02d-%02d-%04d     ", $tm->mon+1, $tm->mday, $tm->year+1900;
printf "%02d:%02d:%02d\n", $tm->hour, $tm->min, $tm->sec;
print "$^X $]   ", "\Net::DNS ", Net::DNS->version, "\n";


    ## PPP0 ADDRESS ##
my $pid = `/bin/cat /var/run/ppp0.pid`
     or die "ppp0 down, abort";
     # abort script if ppp0 down
@ppp = `/sbin/ifconfig ppp0`;
foreach $line (@ppp) {
    if($line =~ /inet addr/) {
    $line =~ s/\s+inet addr:(\S+)\s+.*/$1/;
    $pppip = $line;
    }
}
print "\n\nlocal ppp0\n";
print "================\n";
print "$pppip\n";
# print "$name : ", "$pppip\n";


    ## FORWARD LOOKUPS ##
@ARGV = ("$default" ) unless @ARGV;
my $name = "@ARGV";
print "\n$name forward lookup\n";
print "=============================\n";
my @nameservers=( $ns1, $ns2, $ns3, $ns4 );
my $nameserver;
    foreach $nameserver(@nameservers) {
        print "Nameserver : $nameserver\n";
        my $res = new Net::DNS::Resolver;
        $res->nameservers($nameserver);
        my $query = $res->search("$name");
        if ($query) {
            my $rr;
            foreach $rr ($query->answer) {
                next unless $rr->type eq "A";
                print "$name : ", $rr->address, "\n\n";
            }
        } else {
        print "query failed: ", $res->errorstring, "\n\n";
        }
    }


    ## AUTHORITATIVE NAMESERVERS ##
print "\n$name authoritative nameservers\n";
print   "========================================\n";
my $resNS = new Net::DNS::Resolver;
my $queryNS = $resNS->query("$name", "NS");
if ($queryNS) {
    foreach $rr ($queryNS->answer) {
        next unless $rr->type eq "NS";
        printf "%s\n", $rr->nsdname;
    }
}
else {
    print "\Nameserver query failed: ", $resNS->errorstring, "\n";
}


    ## MX RECORDS ##
print "\n\n$name MX records\n";
print   "==============================\n";
my $resMX = new Net::DNS::Resolver;
@mx = mx($resMX, $name);
if (@mx) {
    foreach $rr (@mx) {
        print $resMX->answerfrom," says : ", $rr->preference, " ", $rr
+->exchange, "\n";
    }
}
else {
    print "MX record query failed: ", $resMX->errorstring, "\n";
}


# END

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In reply to (code) ixnay to nslookupay (first Catacombs submission, ugly nasty bad code) by ybiC

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