외부주소 목록에 nrt ?

실행 ->  cmd - >  netstat 엔터

외부주소목록에 nrt로 뜨는 주소들은 왜 일까요? 

외부주소: 

       nrt20s08-in-f14:https  TIME_WAIT

      121.53.x , x:https   ESTABLISHED

       nrt12s23-in-f10:https  TIME_WAIT

       nrt12s23-in-f10:https  TIME_WAIT

       nrt12s23-in-f14:https  ESTABLISHED

       211.231.x, x :https  ESTABLISHED

       nrt20s09-in-f2:https   TIME_WAIT

       nrt12s36-in-f2:https   TIME_WAIT

       nrt20s21-in-f2:https   TIME_WAIT

       nrt20s09-in-f14:https  ESTABLISHED

       nrt12s14-in-f226:https  TIME_WAIT

       nrt12s14-in-f226:https  TIME_WAIT

       nrt12s29-in-f2:https   TIME_WAIT