NGX_ENETDOWN     1252 src/core/ngx_connection.c         || err == NGX_ENETDOWN
NGX_ENETDOWN      138 src/event/ngx_event_connect.c                 || err == NGX_ENETDOWN
NGX_ENETDOWN     1881 src/event/ngx_event_openssl.c             || err == NGX_ENETDOWN