Index: lib/resolv.rb
===================================================================
--- lib/resolv.rb	(revision 40339)
+++ lib/resolv.rb	(working copy)
@@ -513,29 +513,26 @@
 
     def fetch_resource(name, typeclass)
       lazy_initialize
-      requester = make_udp_requester
+      protocols  = {}
+      requesters = {}
       senders = {}
-      begin
         @config.resolv(name) {|candidate, tout, nameserver, port|
           msg = Message.new
           msg.rd = 1
           msg.add_question(candidate, typeclass)
-          unless sender = senders[[candidate, nameserver, port]]
-            sender = senders[[candidate, nameserver, port]] =
+        protocol  = protocols[candidate| ||= :udp
+        requester = requesters[[protocol, nameserver]] ||= case protocol
+          when :udp then make_udp_requester
+          when :tcp then make_tcp_requester(nameserver, port)
+        end
+        sender    = senders[[candidate, requester, nameserver, port]] ||=
               requester.sender(msg, candidate, nameserver, port)
-          end
           reply, reply_name = requester.request(sender, tout)
           case reply.rcode
           when RCode::NoError
-            if reply.tc == 1 and not Requester::TCP === requester
-              requester.close
+          if protocol == :udp and reply.tc == 1
               # Retry via TCP:
-              requester = make_tcp_requester(nameserver, port)
-              senders = {}
-              # This will use TCP for all remaining candidates (assuming the
-              # current candidate does not already respond successfully via
-              # TCP).  This makes sense because we already know the full
-              # response will not fit in an untruncated UDP packet.
+            protocols[candidate] = :tcp
               redo
             else
               yield(reply, reply_name)
@@ -548,9 +545,8 @@
           end
         }
       ensure
-        requester.close
+      requesters.each_value { |requester| requester.close }
       end
-    end
 
     def make_udp_requester # :nodoc:
       nameserver_port = @config.nameserver_port
@@ -563,6 +559,11 @@
 
     def make_tcp_requester(host, port) # :nodoc:
       return Requester::TCP.new(host, port)
+    rescue Errno::ECONNREFUSED
+      # Treat a refused TCP connection attempt to a nameserver like a timeout,
+      # as Resolv::DNS::Config#resolv considers ResolvTimeout exceptions as a
+      # hint to try the next nameserver:
+      raise ResolvTimeout
     end
 
     def extract_resources(msg, name, typeclass) # :nodoc: