conntrack#

Concept#

Monitoring & Troubleshooting#

real-time conntrack event log#

# conntrack -E
NEW tcp     120 SYN_SENT src=10.1.0.114 dst=10.7.43.52 sport=4123 dport=22 [UNREPLIED] src=10.7.43.52 dst=10.1.0.114 sport=22 dport=4123
UPDATE tcp      60 SYN_RECV src=10.1.0.114 dst=10.7.43.52 sport=4123 dport=22 src=10.7.43.52 dst=10.1.0.114 sport=22 dport=4123
UPDATE tcp  432000 ESTABLISHED src=10.1.0.114 dst=10.7.43.52 sport=4123 dport=22 src=10.7.43.52 dst=10.1.0.114 sport=22 dport=4123 [ASSURED]
UPDATE tcp     120 FIN_WAIT src=10.1.0.114 dst=10.7.43.52 sport=4123 dport=22 src=10.7.43.52 dst=10.1.0.114 sport=22 dport=4123 [ASSURED]
UPDATE tcp      30 LAST_ACK src=10.1.0.114 dst=10.7.43.52 sport=4123 dport=22 src=10.7.43.52 dst=10.1.0.114 sport=22 dport=4123 [ASSURED]
UPDATE tcp     120 TIME_WAIT src=10.1.0.114 dst=10.7.43.52 sport=4123 dport=22 src=10.7.43.52 dst=10.1.0.114 sport=22 dport=4123 [ASSURED]

Tuning#

iptables NAT random local port#

Ref.#