Jobs SIGHUP 默认动作：Terminate 可能动作：Terminate, Ignore, Function call 当检测到 hangup 时，UART 驱动会向整个 session 发送 SIGHUP 信号。 正常情况下，这会 kill 掉所有

Tables↓/Chains→ PREROUTING INPUT FORWARD OUTPUT POSTROUTING (routing decision) ✓ raw ✓ ✓ (connection tracking enabled) ✓ ✓ mangle ✓ ✓ ✓ ✓ ✓ nat (DNAT) ✓ ✓ (routing decision) ✓ ✓ filter ✓ ✓ ✓ security ✓ ✓ ✓ nat (SNAT) ✓ ✓ Incoming packets destined for the local system: PREROUTING -> INPUT Incoming packets destined to another host: PREROUTING -> FORWARD -> POSTROUTING Locally generated packets: OUTPUT -> POSTROUTING Connection Tracking https://arthurchiao.