Big talk command-ss, big talk-ss

Big talk command-ss, big talk-ss

Big talk command-ss

Ss is short for Socket Statistics. As the name suggests, the ss command can be used to obtain socket statistics, which can display content similar to netstat.

Advantages:

(1) display more detailed information about TCP and connection status, (2) faster and more efficient than netstat.

1 format

Format: ss [option]… [Filter]

Netstat traverses proc to obtain socket information. ss uses netlink to communicate with the kernel tcp_diag module to obtain socket information.

2 Option

-T: tcp protocol

-U: udp protocol

-W: bare socket

-L: listen connection

-A: All

-N: digit format

-P: related program and PID

-E: Extended information

-M: memory usage

-O: timer Information

3. Instance

(1) ss-l displays all locally opened ports

[Root @ CentOS68 ~] # Ss-l

State Recv-Q Send-Q Local Address: Port Peer Address: Port

LISTEN 0 128 *: 60455 *:*

LISTEN 0 128: sunrpc :::*

LISTEN 0 128 *: sunrpc *:*

LISTEN 0 128: http :::*

LISTEN 0 128: ssh :::*

LISTEN 0 128 *: ssh *:*

LISTEN 0 128 127.0.0.1: ipp *:*

LISTEN 0 128: 1: ipp :::*

LISTEN 0 100: 1: smtp :::*

LISTEN 0 100 127.0.0.1: smtp *:*

LISTEN 0 128: 39546 :::*

[Root @ CentOS68 ~] #

(2) ss-pl displays the socket opened by each process

[Root @ CentOS68 ~] # Ss-pl

State Recv-Q Send-Q Local Address: Port Peer Address: Port

LISTEN 0 128 *: 60455 *: * users :( ("rpc. statd ))

LISTEN 0 128: sunrpc: * users :( ("rpcbind ))

LISTEN 0 128 *: sunrpc *: * users :( ("rpcbind", 1601,8 ))

LISTEN 0 128 *: ssh *: * users :( ("sshd ))

LISTEN 0 128 127.0.0.1: ipp *: * users :( ("cupsd", 1679,7 ))

LISTEN 0 128: 1: ipp: * users :( ("cupsd", 1679,6 ))

LISTEN 0 100: 1: smtp: * users :( ("master", 1955,13 ))

LISTEN 0 100 127.0.0.1: smtp *: * users :( ("master ))

LISTEN 0 128: 39546: * users :( ("rpc. statd ))

(3)-t-a displays all tcp sockets

[Root @ CentOS68 ~] # Ss-t-

State Recv-Q Send-Q Local Address: Port Peer Address: Port

LISTEN 0 128 *: 60455 *:*

LISTEN 0 128: sunrpc :::*

LISTEN 0 128 *: sunrpc *:*

LISTEN 0 128: http :::*

LISTEN 0 128: ssh :::*

LISTEN 0 128 *: ssh *:*

LISTEN 0 128 127.0.0.1: ipp *:*

LISTEN 0 128: 1: ipp :::*

LISTEN 0 100: 1: smtp :::*

LISTEN 0 100 127.0.0.1: smtp *:*

LISTEN 0 128: 39546 :::*

ESTAB 0 64 192.168.29.68: ssh 192.168.29.1: 50541

(4)-u-a displays all udp sockets

[Root @ CentOS68 ~] # Ss-u-

State Recv-Q Send-Q Local Address: Port Peer Address: Port

UNCONN 0 0 *: sunrpc *:*

UNCONN 0 0 *: 39797 *:*

UNCONN 0 0 *: ipp *:*

UNCONN 0 0 *: 928 *:*

UNCONN 0 0 *: bootpc *:*

UNCONN 0 0 127.0.0.1: 972 *:*

UNCONN 0 0: 59503 :::*

UNCONN 0 0 ::: sunrpc :::*

UNCONN 0 0: 928 :::*

(5) ss-o displays all established connections

[Root @ CentOS68 ~] # Ss-o

State Recv-Q Send-Q Local Address: Port Peer Address: Port

ESTAB 0 64 192.168.29.68: ssh 192.168.29.1: 50541 timer :( on, 442 ms, 0)