From b085388cda28012a1a63da9c3c94225b399ac6a8 Mon Sep 17 00:00:00 2001
From: Matt Simerson <matt@tnpi.net>
Date: Sun, 1 Dec 2013 03:45:12 -0500
Subject: [PATCH] TcpServer: optimize DNS lookups for PTR

a. don't use search path (/etc/resolv.conf)
b. explicitely specify PTR in query request
---
 lib/Qpsmtpd/TcpServer.pm | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/lib/Qpsmtpd/TcpServer.pm b/lib/Qpsmtpd/TcpServer.pm
index 8641576..5651aa4 100644
--- a/lib/Qpsmtpd/TcpServer.pm
+++ b/lib/Qpsmtpd/TcpServer.pm
@@ -191,18 +191,18 @@ sub tcpenv {
         return ($TCPLOCALIP, $TCPREMOTEIP,
                 $TCPREMOTEIP ? "[$ENV{TCPREMOTEIP}]" : "[noip!]");
     }
-    my $res = new Net::DNS::Resolver;
+    my $res = Net::DNS::Resolver->new( dnsrch => 0 );
     $res->tcp_timeout(3);
     $res->udp_timeout(3);
-    my $query = $res->query($nto_iaddr);
+    my $query = $res->query($nto_iaddr, 'PTR');
     my $TCPREMOTEHOST;
     if ($query) {
         foreach my $rr ($query->answer) {
-            next unless $rr->type eq "PTR";
+            next if $rr->type ne 'PTR';
             $TCPREMOTEHOST = $rr->ptrdname;
         }
     }
-    return ($TCPLOCALIP, $TCPREMOTEIP, $TCPREMOTEHOST || "Unknown");
+    return ($TCPLOCALIP, $TCPREMOTEIP, $TCPREMOTEHOST || 'Unknown');
 }
 
 sub check_socket() {