how to get internet while your default policy is DROP in iptables

Zak A

6/4/23, 4:59 AM

basically I want to block all unauthorized traffic with iptables I set my default policy to drop (INPUT) and that caused me to not have internet which is understandable , I know I have to set a rule to get internet which rule would that be?

0 + 0

server

iptables

networking

internet

pLumo

6/4/23, 7:54 AM

This is not answerable. Not sure what you want. "Internet" is the whole thing, and services can use any port they like. If you mean websites (HTTP) you need ports 80 and 443, sometimes 8080, but any other port is also allowed. Or do you mean SSH (22) or FTP (21), SMTP , Pop3, IMAP .... also don't forget DNS queries (53) and many more ... all have different **default** ports. Please tell us your goal. The default setup that outgoing traffic is allowed per default is good for general purpose. You may rather want to use an application-based firewall like opensnitch or douane?

Nate T

6/5/23, 4:42 AM

I doubt he or she will be accepting DNS queries, but I get your point. XD

Score:2

Ubuntu

karel

6/5/23, 4:13 AM

The default firewall configuration tool for Ubuntu is ufw (uncomplicated firewall). If you want to reset ufw, you need to run the sudo ufw reset command. This command will basically set the ufw firewall back to its default settings. Open the terminal and type:

sudo apt update
sudo apt install ufw
sudo ufw reset  
sudo ufw enable # type y at the [Y/n] prompt

After running these commands run sudo ufw status verbose to check the status of UFW. The output should be like this:

$ sudo ufw status verbose
Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing), deny (routed)
New profiles: skip

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Elon Musk

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

EN: how to get internet while your default policy is DROP in iptables

TH: วิธีรับอินเทอร์เน็ตในขณะที่นโยบายเริ่มต้นของคุณคือ DROP ใน iptables

RO: cum să obțineți internet în timp ce politica dvs. implicită este DROP în iptables

RU: как получить интернет, когда ваша политика по умолчанию DROP в iptables

VI: cách truy cập internet trong khi chính sách mặc định của bạn là DROP trong iptables

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