NGX_EHOSTUNREACH 1052 core/ngx_connection.c         || err == NGX_EHOSTUNREACH)
NGX_EHOSTUNREACH  151 event/ngx_event_connect.c                 || err == NGX_EHOSTUNREACH)
NGX_EHOSTUNREACH 1291 event/ngx_event_openssl.c             || err == NGX_EHOSTUNREACH)