[root@centos8 ~]# ss
Netid     State      Recv-Q      Send-Q                             Local Address:Port             Peer Address:Port       
u_str     ESTAB      0           0                                              * 197094                      * 198007     
u_str     ESTAB      0           0                                              * 197087                      * 198001     


u_str     ESTAB      0           0                                              * 195091                      * 195676     
tcp       ESTAB      0           0                                    



[root@centos8 ~]# ss
Netid     State      Recv-Q      Send-Q                             Local Address:Port             Peer Address:Port  


名称 説明
Netid プロトコル名(tcp、udp、u_str…)
State ソケットの状態
Recv-Q 受信しなかったデータのバイト数
Send-Q 送信しなかったデータのバイト数
Local Address:Port ソケットに紐づくローカルホスト名またはIPアドレス、ポート番号
Peer Address:Port リモートホストのホスト名またはIPアドレス、ポート番号





名称 説明
-a 全てのソケット情報を表示
-s 各プロトコルの統計情報を表示
-l 接続待ち状態のソケットのみを表示
-n ネットワークアドレスを表示
-t TCPソケット情報を表示
-u UDPソケット情報を表示
-x UNIXドメインソケット情報を表示



[root@centos8 /]# ss --help
Usage: ss [ OPTIONS ]
       ss [ OPTIONS ] [ FILTER ]
   -h, --help          this message
   -V, --version       output version information
   -n, --numeric       don't resolve service names
   -r, --resolve       resolve host names
   -a, --all           display all sockets
   -l, --listening     display listening sockets
   -o, --options       show timer information
   -e, --extended      show detailed socket information
   -m, --memory        show socket memory usage
   -p, --processes     show process using socket
   -i, --info          show internal TCP information
       --tipcinfo      show internal tipc socket information
   -s, --summary       show socket usage summary
       --tos           show tos and priority information
   -b, --bpf           show bpf filter socket information
   -E, --events        continually display sockets as they are destroyed
   -Z, --context       display process SELinux security contexts
   -z, --contexts      display process and socket SELinux security contexts
   -N, --net           switch to the specified network namespace name

   -4, --ipv4          display only IP version 4 sockets
   -6, --ipv6          display only IP version 6 sockets
   -0, --packet        display PACKET sockets
   -t, --tcp           display only TCP sockets
   -S, --sctp          display only SCTP sockets
   -u, --udp           display only UDP sockets
   -d, --dccp          display only DCCP sockets
   -w, --raw           display only RAW sockets
   -x, --unix          display only Unix domain sockets
       --tipc          display only TIPC sockets
       --vsock         display only vsock sockets
   -f, --family=FAMILY display sockets of type FAMILY
       FAMILY := {inet|inet6|link|unix|netlink|vsock|tipc|xdp|help}

   -K, --kill          forcibly close sockets, display what was closed
   -H, --no-header     Suppress header line
   -O, --oneline       socket's data printed on a single line

   -A, --query=QUERY, --socket=QUERY
       QUERY := {all|inet|tcp|udp|raw|unix|unix_dgram|unix_stream|unix_seqpacket|packet|netlink|vsock_stream|vsock_dgram|tipc}[,QUERY]

   -D, --diag=FILE     Dump raw information about TCP sockets to FILE
   -F, --filter=FILE   read filter information from FILE
       FILTER := [ state STATE-FILTER ] [ EXPRESSION ]
       STATE-FILTER := {all|connected|synchronized|bucket|big|TCP-STATES}
         TCP-STATES := {established|syn-sent|syn-recv|fin-wait-{1,2}|time-wait|closed|close-wait|last-ack|listening|closing}
          connected := {established|syn-sent|syn-recv|fin-wait-{1,2}|time-wait|close-wait|last-ack|closing}
       synchronized := {established|syn-recv|fin-wait-{1,2}|time-wait|close-wait|last-ack|closing}
             bucket := {syn-recv|time-wait}
                big := {established|syn-sent|fin-wait-{1,2}|closed|close-wait|last-ack|listening|closing}