节点mdns dns服务错误

我试图用mdns节点模块实现zeroconf protocole,但是当我使用它时我有这个错误(在树莓pi 2上):

error: Error: dns service error: unknown at Error (native) at new Advertisement (/var/www/lisa/node_modules/mdns/lib/advertisement.js:56:10) at Object.create [as createAdvertisement] (/var/www/lisa/node_modules/mdns/lib/advertisement.js:64:10) at Object.module.exports.bootstrap (/var/www/lisa/config/bootstrap.js:22:17) at Sails.runBootstrap (/var/www/lisa/node_modules/sails/lib/app/private/bootstrap.js:44:25) at Sails.bound [as runBootstrap] (/var/www/lisa/node_modules/sails/node_modules/lodash/dist/lodash.js:729:21) at Sails.initialize (/var/www/lisa/node_modules/sails/lib/app/private/initialize.js:48:9) at bound (/var/www/lisa/node_modules/sails/node_modules/lodash/dist/lodash.js:729:21) at /var/www/lisa/node_modules/sails/node_modules/async/lib/async.js:607:21 at /var/www/lisa/node_modules/sails/node_modules/async/lib/async.js:246:17 at iterate (/var/www/lisa/node_modules/sails/node_modules/async/lib/async.js:146:13) at /var/www/lisa/node_modules/sails/node_modules/async/lib/async.js:157:25 at /var/www/lisa/node_modules/sails/node_modules/async/lib/async.js:248:21 at /var/www/lisa/node_modules/sails/node_modules/async/lib/async.js:612:34 at /var/www/lisa/node_modules/sails/lib/app/load.js:201:13 at /var/www/lisa/node_modules/sails/node_modules/async/lib/async.js:451:17 

这是我的代码:

 var mdns = require('mdns'); var txt_record = { name : 'Test module' }; var ad = mdns.createAdvertisement(mdns.tcp('http'), 4321, txt_record); ad.start();