diff --git a/extensions/dns/api.rb b/extensions/dns/api.rb
index ca0accd456..60c9d3927e 100644
--- a/extensions/dns/api.rb
+++ b/extensions/dns/api.rb
@@ -49,7 +49,7 @@ def self.pre_http_start(http_hook_server)
               end
             end
 
-            Thread.new { EventMachine.next_tick { dns.run(:upstream => servers, :listen => interfaces) } }
+            dns.run(:upstream => servers, :listen => interfaces)
 
             print_info "DNS Server: #{address}:#{port} (#{protocol})"
             print_more upstream_servers
diff --git a/extensions/dns/dns.rb b/extensions/dns/dns.rb
index e01271cdde..177414c5db 100644
--- a/extensions/dns/dns.rb
+++ b/extensions/dns/dns.rb
@@ -113,15 +113,19 @@ def remove_ruleset!
         # @option options [Array<Array>] :listen local interfaces to listen on
         def run(options = {})
           @lock.synchronize do
-            upstream = options[:upstream]
-            listen = options[:listen]
+            Thread.new do
+              EventMachine.next_tick do
+                upstream = options[:upstream] || nil
+                listen = options[:listen] || nil
+
+                if upstream
+                  resolver = RubyDNS::Resolver.new(upstream)
+                  @otherwise = Proc.new { |t| t.passthrough!(resolver) }
+                end
 
-            unless upstream.nil? || upstream.empty?
-              resolver = RubyDNS::Resolver.new(upstream)
-              @otherwise = Proc.new { |t| t.passthrough!(resolver) }
+                super(:listen => listen)
+              end
             end
-
-            super(:listen => listen)
           end
         end