49 lines
1.0 KiB
Plaintext
49 lines
1.0 KiB
Plaintext
use Net::DNS qw(mx);
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sub register {
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my ($self, $qp) = @_;
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$self->register_hook("mail", "mail_handler");
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}
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sub mail_handler {
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my ($self, $transaction, $sender) = @_;
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$sender->format ne "<>"
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and $self->qp->config("require_resolvable_fromhost")
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and !check_dns($sender->host)
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and return (DENYSOFT,
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($sender->host
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? "Could not resolve ". $sender->host
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: "FQDN required in the envelope sender"));
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return DECLINED;
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}
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sub check_dns {
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my $host = shift;
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# for stuff where we can't even parse a hostname out of the address
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return 0 unless $host;
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return 1 if $host =~ m/^\[(\d{1,3}\.){3}\d{1,3}\]$/;
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my $res = new Net::DNS::Resolver;
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$res->tcp_timeout(30);
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$res->udp_timeout(30);
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return 1 if mx($res, $host);
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my $query = $res->search($host);
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if ($query) {
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foreach my $rr ($query->answer) {
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return 1 if $rr->type eq "A" or $rr->type eq "MX";
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}
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}
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else {
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warn "$$ query for $host failed: ", $res->errorstring, "\n"
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unless $res->errorstring eq "NXDOMAIN";
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}
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return 0;
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}
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