Conditional port forwarding with ufw as a default policy

Stephen Willson

10/27/22, 1:01 AM

Is there a way such that: when a connection is denied (by the rule set) in ufw, it forwards that traffic to another port on the local machine, rather than dropping (by default)?

I can see two potential ways for port forwarding in ufw, I am wondering how to modify these so that it is conditional.

Adding -A PREROUTING rule to /etc/ufw/before.rules. But I need that rule only to be applied when the connection should not be allowed (as defined in the ufw rules). In other words, as the default rule (to forward instead of block).
sudo ufw route, but how to apply that route only for denied connections? The example I see does not have a condition set. (set that as a catch-all default policy). Is it possible to add route as the default rule for connections?

115

0 + 2

security

ubuntu

firewall

iptables

ufw

Michael Hampton

10/27/22, 1:17 AM

In that case you are not dropping the traffic at all! You are just port forwarding.

Stephen Willson

10/27/22, 1:20 AM

@MichaelHampton That's right. I have updated the title and content accordingly. Thanks!

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Conditional port forwarding with ufw as a default policy

TH: การส่งต่อพอร์ตแบบมีเงื่อนไขด้วย ufw เป็นนโยบายเริ่มต้น

RO: Redirecționarea portului condiționat cu ufw ca politică implicită

RU: Условная переадресация портов с ufw в качестве политики по умолчанию

VI: Chuyển tiếp cổng có điều kiện với ufw làm chính sách mặc định

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