Iptables-tracer

Утилита, позволяющая отследить путь прохождения пакетов через цепочки iptables на сервере.

Использование

$ iptables-tracer -f "-s 192.0.2.1 -p tcp --dport 443" -t 30s
14:42:00.284882 raw PREROUTING 0x00000000 IP 192.0.2.1.36028 > 203.0.113.41.443: Flags [S], seq 3964691400, win 29200, length 0 [In:eth0 Out:]
14:42:00.287255 mangle PREROUTING 0x00008000 IP 192.0.2.1.36028 > 203.0.113.41.443: Flags [S], seq 3964691400, win 29200, length 0 [In:eth0 Out:]
14:42:00.288966 nat PREROUTING 0x00008000 IP 192.0.2.1.36028 > 203.0.113.41.443: Flags [S], seq 3964691400, win 29200, length 0 [In:eth0 Out:]
14:42:00.290545 mangle FORWARD 0x00008000 IP 192.0.2.1.36028 > 198.51.100.8.443: Flags [S], seq 3964691400, win 29200, length 0 [In:eth0 Out:eth1]
14:42:00.292123 filter FORWARD 0x00008002 IP 192.0.2.1.36028 > 198.51.100.8.443: Flags [S], seq 3964691400, win 29200, length 0 [In:eth0 Out:eth1]
14:42:00.293164 mangle POSTROUTING 0x00008002 IP 192.0.2.1.36028 > 198.51.100.8.443: Flags [S], seq 3964691400, win 29200, length 0 [In: Out:eth1]
14:42:00.293780 nat POSTROUTING 0x00008002 IP 192.0.2.1.36028 > 198.51.100.8.443: Flags [S], seq 3964691400, win 29200, length 0 [In: Out:eth1]

https://github.com/x-way/iptables-tracer

👉 @sysadminof