detect error when localhost is not binding

[fengmk2]

detect-port detect free port between [8003, 8013) +0ms
  detect-port get free null:8003 +7ms
  detect-port listen localhost:8003 error: Error: getaddrinfo ENOTFOUND localhost +5ms
  detect-port get free null:8004 +1ms
  detect-port listen localhost:8004 error: Error: getaddrinfo ENOTFOUND localhost +2ms
  detect-port get free null:8005 +0ms
  detect-port listen localhost:8005 error: Error: getaddrinfo ENOTFOUND localhost +1ms
  detect-port get free null:8006 +0ms
  detect-port listen localhost:8006 error: Error: getaddrinfo ENOTFOUND localhost +1ms
  detect-port get free null:8007 +0ms
  detect-port listen localhost:8007 error: Error: getaddrinfo ENOTFOUND localhost +1ms
  detect-port get free null:8008 +0ms
  detect-port listen localhost:8008 error: Error: getaddrinfo ENOTFOUND localhost +1ms
  detect-port get free null:8009 +0ms
  detect-port listen localhost:8009 error: Error: getaddrinfo ENOTFOUND localhost +1ms
  detect-port get free null:8010 +0ms
  detect-port listen localhost:8010 error: Error: getaddrinfo ENOTFOUND localhost +1ms
  detect-port get free null:8011 +0ms
  detect-port listen localhost:8011 error: Error: getaddrinfo ENOTFOUND localhost +1ms
  detect-port get free null:8012 +0ms
  detect-port listen localhost:8012 error: Error: getaddrinfo ENOTFOUND localhost +1ms
  detect-port port: 8013 >= maxPort: 8013, give up and use random port +0ms
  detect-port get free null:56846 +0ms
port 8003 was occupied
get available port 56846