diff --git a/modules/auxiliary/spoof/nbns/nbns_response.rb b/modules/auxiliary/spoof/nbns/nbns_response.rb
index 2b1cd69b59..0916ac71dd 100644
--- a/modules/auxiliary/spoof/nbns/nbns_response.rb
+++ b/modules/auxiliary/spoof/nbns/nbns_response.rb
@@ -67,6 +67,7 @@ class Metasploit3 < Msf::Auxiliary
 
     while @run # Not exactly thrilled we can never turn this off XXX fix this sometime.
       packet, addr = @sock.recvfrom(512)
+      src_port = addr[1]
       rhost = addr[3]
 
       break if packet.length == 0
@@ -127,7 +128,7 @@ class Metasploit3 < Msf::Auxiliary
         p.ip_daddr = rhost
         p.ip_ttl = 255
         p.udp_sport = 137
-        p.udp_dport = 137
+        p.udp_dport = src_port
         p.payload = response
         p.recalc