Added some zone checks:
* check if NS records are consistent * compare zones from all authoritative name servers
This commit is contained in:
hjp
parent
d6329c4c03
commit
888f0a58eb
218
dns/check.pl
218
dns/check.pl
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@ -9,13 +9,18 @@ sub usage {
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usage() unless (@ARGV == 1);
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my $res = new Net::DNS::Resolver;
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# generic resolver
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my $res0 = new Net::DNS::Resolver;
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# special resolver to query specific nameservers
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my $res1 = new Net::DNS::Resolver;
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my $zone;
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if ($ARGV[0] =~ m/^(\d+)\.(\d+)\.(\d+)\.(\d+)$/) {
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check_ptr($ARGV[0]);
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} else {
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check_a($ARGV[0]);
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# check_ns($ARGV[0]);
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}
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check_zone($ARGV[0]) if ($zone);
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exit 0;
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@ -31,7 +36,7 @@ sub check_ptr {
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} else {
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# XXX - ipv6?
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my $q = join('.', reverse (split(/\./, $addr)), "in-addr", "arpa");
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my $reply = $res->send($q, 'PTR');
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my $reply = $res0->send($q, 'PTR');
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for my $ans ($reply->answer) {
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if ($ans->type eq 'PTR') {
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push @names, $ans->ptrdname;
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@ -43,6 +48,7 @@ sub check_ptr {
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print "[$addr] $q has no PTR record\n";
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}
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$addr_to_name{$addr} = \@names;
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get_zone($reply) unless $zone;
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}
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if ($name) {
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unless (grep { $_ eq $name } @names) {
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@ -62,19 +68,22 @@ sub check_a {
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if (defined $name_to_addr{$name}) {
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@addrs = @{ $name_to_addr{$name} };
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} else {
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my $reply = $res->send($name, 'A');
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my $reply = $res0->send($name, 'A');
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for my $ans ($reply->answer) {
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if ($ans->type eq 'A') {
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push @addrs, $ans->address;
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} elsif ($ans->type eq 'CNAME') {
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die "cnames not yet supported";
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} else {
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print "unexpected response to A query for $name\n";
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$ans->print;
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}
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}
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if (@addrs == 0) {
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if (@addrs == 0) {
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print "$name has no A record\n";
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}
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$name_to_addr{$name} = \@addrs;
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get_zone($reply) unless $zone;
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}
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if ($addr) {
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unless (grep { $_ eq $addr } @addrs) {
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@ -87,11 +96,198 @@ sub check_a {
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}
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}
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my $answer = $res->query($ARGV[0], $ARGV[1]);
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if ($answer) {
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$answer->print;
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} else {
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print STDERR "query failed: ", $res->errorstring, "\n";
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sub get_zone {
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my ($reply) = @_;
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for my $auth ($reply->authority) {
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if (defined $zone) {
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if ($zone ne $auth->name) {
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print "inconsistent authority RRs:\n";
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print $auth->print;
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print "doesn't match previously found zone $zone\n";
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}
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} else {
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$zone = $auth->name;
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}
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}
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}
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# $res->nameservers($ARGV[2]);
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sub check_zone {
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my ($name) = @_;
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my $rootns = chr(rand(13) + 65) . ".root-servers.net.";
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my $reply = $res0->send($rootns, 'A');
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my @ns = (($reply->answer)[0]->address);
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my %authns;
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my %seen;
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while (@ns) {
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my $ns = shift (@ns);
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$res1->nameservers($ns);
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my $reply = $res1->send($zone, 'NS');
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# if the reply contains a non-empty answer section, use it as
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# a list of authoritative name servers.
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if ($reply->answer) {
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for my $rr ($reply->answer) {
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if ($rr->type eq 'NS') {
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print STDERR "$ns reported NS ", $rr->nsdname, "\n";;
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$authns{$ns}{$rr->nsdname} = 1;
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$authns{ALL}{$rr->nsdname} = 1;
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for (get_addresses($rr->nsdname)) {
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unless ($seen{$_}) {
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push @ns, $_;
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$seen{$_} = 1;
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}
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}
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}
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}
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next;
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}
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#
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if ($reply->authority) {
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for my $rr ($reply->authority) {
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if ($rr->type eq 'NS') {
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if ($rr->name eq $name) {
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# if the reply contains an authority section with the right
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# domain, use it as a list of authoritative name servers.
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print STDERR "$ns reported NS ", $rr->nsdname, "\n";;
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$authns{$ns}{$rr->nsdname} = 1;
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$authns{ALL}{$rr->nsdname} = 1;
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for (get_addresses($rr->nsdname)) {
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unless ($seen{$_}) {
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push @ns, $_;
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$seen{$_} = 1;
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}
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}
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} else {
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# Otherwise, just add the nameservers from the authority section
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# to the list of nameservers still to query.
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for (get_addresses($rr->nsdname)) {
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unless ($seen{$_}) {
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push @ns, $_;
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$seen{$_} = 1;
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}
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}
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}
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}
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}
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next;
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}
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}
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# We must make sure that we get a result from all authoritative
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# name servers
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#
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# XXX
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#
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# Isn't that included in the next test? If an authoritative
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# nameserver doesn't answer, it will be reported as not reporting
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# all nameservers.
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# All lists of nameservers must be identical.
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#
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for my $authns (sort keys %{ $authns{ALL} }) {
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for my $origns (sort keys %authns) {
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print "$origns doesn't report $authns\n" unless $authns{$origns}{$authns};
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}
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}
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my @noaxfr;
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my %zone;
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for my $authns (sort keys %{ $authns{ALL} }) {
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$res1->nameservers($authns);
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my @zone = $res1->axfr($zone);
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push @noaxfr, $authns unless @zone;
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for my $rr (@zone) {
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my $key = rr2key($rr);
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$zone{$authns}{$rr->name}{$rr->type}{$key} = 1;
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$zone{ALL}{$rr->name}{$rr->type}{$key} = 1;
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}
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}
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for my $authns (@noaxfr) {
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$res1->nameservers($authns);
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for my $name (sort keys %{ $zone{ALL} }) {
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for my $type (sort keys %{ $zone{ALL}{$name} }) {
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my $reply = $res1->send($name, $type);
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for my $rr ($reply->answer) {
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if ($rr->type eq $type) {
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my $key = rr2key($rr);
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$zone{$authns}{$rr->name}{$rr->type}{$key} = 1;
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$zone{ALL}{$rr->name}{$rr->type}{$key} = 1;
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}
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}
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}
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}
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}
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for my $authns (sort keys %zone) {
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# next if $authns eq 'ALL';
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for my $name (sort keys %{ $zone{ALL} }) {
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for my $type (sort keys %{ $zone{ALL}{$name} }) {
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for my $key (sort keys %{ $zone{ALL}{$name}{$type} }) {
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unless ($zone{$authns}{$name}{$type}{$key}) {
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print STDERR "$authns is missing $name $type $key\n";
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}
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}
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}
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}
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}
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}
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sub get_addresses {
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my ($name) = @_;
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my @addrs;
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my $reply = $res0->send($name, 'A');
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for my $rr ($reply->answer) {
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if ($rr->type eq 'A') {
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push @addrs, $rr->address;
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}
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# XXX - resolve CNAMEs?
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}
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return @addrs;
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}
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sub rr2key {
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my ($rr) = @_;
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my $key;
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if ($rr->type eq 'A') {
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$key = $rr->address;
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} elsif ($rr->type eq 'SOA') {
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$key = join(' ', $rr->mname, $rr->rname, $rr->serial, $rr->refresh, $rr->retry, $rr->expire, $rr->minimum);
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} elsif ($rr->type eq 'NS') {
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$key = $rr->nsdname;
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} elsif ($rr->type eq 'MX') {
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$key = join(' ', $rr->preference, $rr->exchange);
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} else {
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print STDERR "unhandled RR:\n";
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print STDERR $rr->string, "\n";
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exit(1);
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}
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return $key;
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}
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# Notes:
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#
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# for every a record, check ptr.
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#
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# for every ptr, check a
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#
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# find the zone (authority section).
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#
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# Check name servers (starting at random root).
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#
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# Try axfr.
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# check each record:
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# the same on all nameservers?
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# A to PTR and vice versa
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# MX
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#
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# vim: tw=0 sw=4 expandtab
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