Resolved DNS thread issue using EM::next_tick() instead of sleep().

extensions/dns/api.rb

@@ -20,10 +20,7 @@ module API
       address = config.get('beef.extension.dns.address')
       port    = config.get('beef.extension.dns.port')
 
-      Thread.new do
-        sleep 2
-        BeEF::Extension::DNS::DNS.new(address, port)
-      end
+      Thread.new { BeEF::Extension::DNS::DNS.new(address, port) }
 
       print_info "DNS Server: #{address}:#{port}"
     end

extensions/dns/dns.rb

@@ -15,7 +15,7 @@ module DNS
       @address = address
       @port = port
 
-      run_server
+      EventMachine::next_tick { run_server }
     end
 
     def run_server