Notes commandes ss netstat et autres

Voir :

• nstat
• hping2

Voir aussi :

• tcpdump
• Wireshark
• syntaxe BPF Berkeley Packet Filter

ss --tcp state CLOSE-WAIT
ss --tcp state CLOSE-WAIT --kill

/proc/sys/net/ipv4/tcp_keepalive_time

Voir :

• http://www4.cs.fau.de/Projects/JX/Projects/TCP/tcpstate.html
• https://qastack.fr/ubuntu/538443/whats-the-difference-between-port-status-listening-time-wait-close-wait
• https://www.thegeekdiary.com/high-number-of-connections-is-close_wait-state-in-netstat-command-output/
• https://lafibre.info/tcpip/time_wait/
• https://blog.cloudflare.com/this-is-strictly-a-violation-of-the-tcp-specification/

ss -tn -4 state established not src 127.0.0.1
ss -n -t src :5455

# ss -s
Total: 281 (kernel 3060)
TCP:   10 (estab 4, closed 0, orphaned 0, synrecv 0, timewait 0/0), ports 0

Transport Total     IP        IPv6
*         3060      -         -
RAW       0         0         0
UDP       2         2         0
TCP       10        7         3
INET      12        9         3
FRAG      0         0         0

Voir /proc/net/netstat

netstat -nat |sed '2d' | awk '{print $6}' | sort | uniq -c | sort -n

      1 Foreign
      4 SYN_RECV
     12 LISTEN
    131 ESTABLISHED
    191 CLOSE_WAIT
    270 TIME_WAIT

Source: https://www.skyminds.net/serveur-dedie-reduire-les-connexions-time_wait-des-sockets-et-optimiser-tcp/

C'est l'équivalent de

ss -s