69 lines
1.7 KiB
Perl
Executable File
69 lines
1.7 KiB
Perl
Executable File
#!/usr/bin/perl -w
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use strict;
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use Net::DNS;
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sub usage {
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print STDERR "Usage: $0 ip-address\n";
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exit(1);
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}
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usage() unless (@ARGV == 1);
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# generic resolver
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my $res0 = new Net::DNS::Resolver;
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my $ipv4 = $ARGV[0];
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my $rev_domain = join(".", reverse (split(/\./, $ipv4)), "in-addr", "arpa");
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print STDERR "$rev_domain\n";
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my $reply = $res0->send($rev_domain, 'PTR');
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if ($reply->answer) {
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for my $rr ($reply->answer) {
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if ($rr->type eq 'PTR') {
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print STDERR "\t", $rr->ptrdname, "\n";
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check_a($rr->ptrdname, $ipv4);
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}
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}
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} elsif ($reply->authority) {
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for my $rr ($reply->authority) {
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if ($rr->type eq 'SOA') {
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print STDERR "\t", $rr->mname, "\n";
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my $res1 = Net::DNS::Resolver->new();
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$res1->nameservers($rr->mname);
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my @zone = $res1->axfr($rev_domain);
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for my $rr (@zone) {
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if ($rr->type eq 'PTR') {
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print STDERR "\t\t", $rr->ptrdname, "\n";
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my $ipv4 = join(".", (reverse(split(/\./, $rr->name)))[2..5]);
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check_a($rr->ptrdname, $ipv4);
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}
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}
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}
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}
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} else {
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$reply->print
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}
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sub check_a {
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my ($domain_name, $a) = @_;
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# check that $domain_name resolves to $a
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my $reply = $res0->send($domain_name, 'A');
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if ($reply->answer) {
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for my $rr ($reply->answer) {
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if ($rr->type eq 'A') {
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print STDERR "\t\t", $rr->address, "\n";
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if ($rr->address eq $a) {
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print STDERR "\t\t\tfound\n";
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return 1;
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}
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}
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}
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}
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print " $a $domain_name FWD_FAIL\n";
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return 0;
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}
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