Number of Linux concurrent connections view

1. View the number of concurrent requests for the Web server (Nginx Apache) and its TCP connection status:

Netstat-n | awk '/^tcp/{++s[$NF]} END {for (a in S) print A, s[a]} '

Netstat-n|grep ^tcp|awk ' {print $NF} ' |sort-nr|uniq-c

Or:
Netstat-n | awk '/^tcp/{++state[$NF]} END {for (key in) print key, "T", State[key]} '
The returned results are generally as follows:

Last_ack 5 (number of requests waiting to be processed)
SYN_RECV 30
Established 1597 (normal data transfer status)
Fin_wait1 51
Fin_wait2 504
Time_wait 1057 (number of requests processed, waiting for timeout to end)

Additional parameter Description:

CLOSED: No connection is active or in progress
LISTEN: The server is waiting to enter the call
SYN_RECV: A connection request has arrived, waiting for confirmation
Syn_sent: Application has started, open a connection
Established: Normal data transfer status
FIN_WAIT1: Application says it's done
Fin_wait2: The other side has agreed to release
Itmed_wait: Waiting for all packets to die
CLOSING: Both sides try to close simultaneously
Time_wait: The other side has initialized a release
Last_ack: Waiting for all packets to die

2. View the number of Nginx running processes
Ps-ef | grep Nginx | Wc-l
The number returned is the number of nginx running processes, and if Apache executes
Ps-ef | grep httpd | Wc-l

3. View the number of Web server process connections:
NETSTAT-ANTP | grep 80 | grep established-c

Number of Linux concurrent connections view