为什么本地主机进程之间的ESTABLISHED连接状态显示两次？

Question

类似于nginx和php-fpm。 netstat -anpt|grep 9000 tcp 0 0 127.0.0.1:9000 0.0.0.0:* LISTEN 926/php-fpm: pool w tcp 0 0 127.0.0.1:9000 127.0.0.1:59895 ESTABLISHED 12996/php-fpm: pool tcp 0 0 127.0.0.1:60094 127.0.0.1:9000 ESTABLISHED 11429/nginx: worker tcp 0 0 127.0.0.1:60068 127.0.0.1:9000 ESTABLISHED 11423/nginx: worker tcp 0 0 127.0.0.1:9000 127.0.0.1:60424 ESTABLISHED 13015/php-fpm: pool tcp 0 0 127.0.0.1:9000 127.0.0.1:60189 ESTABLISHED 926/php-fpm: pool w tcp 0 0 127.0.0.1:59885 127.0.0.1:9000 ESTABLISHED 11430/nginx: worker tcp 0 0 127.0.0.1:9000 127.0.0.1:59902 ESTABLISHED 13023/php-fpm: pool tcp 0 0 127.0.0.1:59895 127.0.0.1:9000 ESTABLISHED 11431/nginx: worker tcp 0 0 127.0.0.1:9000 127.0.0.1:60068 ESTABLISHED 13247/php-fpm: pool tcp 0 0 127.0.0.1:9000 127.0.0.1:21065 ESTABLISHED 13469/php-fpm: pool tcp 0 0 127.0.0.1:9000 127.0.0.1:60972 ESTABLISHED 13965/php-fpm: pool tcp 0 0 127.0.0.1:59906 127.0.0.1:9000 ESTABLISHED 11421/nginx: worker tcp 0 0 127.0.0.1:9000 127.0.0.1:59891 ESTABLISHED 13936/php-fpm: pool tcp 0 0 127.0.0.1:9000 127.0.0.1:59948 ESTABLISHED 12988/php-fpm: pool tcp 0 0 127.0.0.1:59889 127.0.0.1:9000 ESTABLISHED 11429/nginx: worker tcp 0 0 127.0.0.1:21069 127.0.0.1:9000 ESTABLISHED 11427/nginx: worker tcp 0 0 127.0.0.1:60143 127.0.0.1:9000 ESTABLISHED 11424/nginx: worker tcp 0 0 127.0.0.1:9000 127.0.0.1:60011 ESTABLISHED 13818/php-fpm: pool tcp 0 0 127.0.0.1:9000 127.0.0.1:60349 ESTABLISHED 1950/php-fpm: pool tcp 0 0 127.0.0.1:9000 127.0.0.1:59930 ESTABLISHED 14521/php-fpm: pool tcp 0 0 127.0.0.1:9000 127.0.0.1:59889 ESTABLISHED 12968/php-fpm: pool ... 我只是粘贴部分输出。我想问的是，为什么一个已建立的连接（在localhost进程之间）状态在这里显示两次？