OpenAI made pf.conf for home use

[psypro]

Question :
Openbsd of Nat for home firewall . pf.conf


Answer :

OpenBSD's pf firewall is a popular choice for home firewall applications due to its ease of use and strong security features. Here's a basic example of a pf.conf file for a home firewall:

.  # Define network interfaces
ext_if = "em0"
int_if = "em1"

# Set default policies
set block-policy drop
set loginterface $ext_if

# Block spoofed packets
block in quick from urpf-failed

# Block incoming packets from the Internet to internal network
block in on $ext_if from any to 192.168.1.0/24

# Allow outgoing traffic from internal network to the Internet
pass out on $ext_if from 192.168.1.0/24 to any keep state

# Allow established connections
pass in on $ext_if proto tcp from any to any port ssh flags S/SA keep state

# Block all other incoming traffic from the Internet
block in on $ext_if from any to any

# Allow traffic between internal network and firewall
pass in on $int_if from 192.168.1.0/24 to $int_if keep state
pass out on $int_if from $int_if to 192.168.1.0/24 keep state

This example sets the external interface to em0 and the internal interface to em1. It then sets the default policy to drop and logs any traffic that is blocked. It also blocks spoofed packets and incoming traffic from the Internet to the internal network. Outgoing traffic from the internal network to the Internet is allowed, as are established connections and traffic between the internal network and the firewall. All other incoming traffic from the Internet is blocked.

Of course, this is just a basic example, and the pf.conf file can be customized to meet specific security needs and requirements. It's important to thoroughly understand the pf.conf syntax and the security implications of each rule before implementing a firewall configuration in a production environment.

[J65nko]

• The leading '.' at the beginning of the rule set is an error (pasting?).
  
• With a default policy of blocking all traffic : block log all, then you only have to specify the traffic that is allowed (in or out). All other traffic will be dropped by the default policy......
• There is no NAT rule.

How did ChatGPT know about the 192.168.1.0/24 net block? It could have used [b]$int_if:network ....

[psypro]

I posted it on forum, I get feedback this will not provide NAT. Does your sample pf.conf provide NAT?

No, the sample pf.conf that I provided does not include NAT (Network Address Translation) rules. NAT is used to map private IP addresses to public IP addresses, allowing devices on a private network to access the Internet.

Here's an example of how to add NAT rules to the pf.conf file:

Define network interfaces

ext_if = "em0"
int_if = "em1"

Set default policies

set block-policy drop
set loginterface $ext_if

Block spoofed packets

block in quick from urpf-failed

Block incoming packets from the Internet to internal network

block in on $ext_if from any to 192.168.1.0/24

Allow outgoing traffic from internal network to the Internet and perform NAT

pass out on $ext_if from 192.168.1.0/24 to any nat-to ($ext_if)

Allow established connections

pass in on $ext_if proto tcp from any to any port ssh flags S/SA keep state

Block all other incoming traffic from the Internet

block in on $ext_if from any to any

Allow traffic between internal network and firewall

pass in on $int_if from 192.168.1.0/24 to $int_if keep state
pass out on $int_if from $int_if to 192.168.1.0/24 keep state

This code adds a NAT rule to allow outgoing traffic from the internal network to the Internet, and performs NAT using the external interface ($ext_if).

Note that this is just an example, and the specific NAT rules may need to be adjusted depending on the network setup and requirements.

# Define network interfaces
ext_if = "em0"
int_if = "em1"

# Set default policies
set block-policy drop
set loginterface $ext_if

# Block spoofed packets
block in quick from urpf-failed

# Block incoming packets from the Internet to internal network
block in on $ext_if from any to 192.168.1.0/24

# Allow outgoing traffic from internal network to the Internet and perform NAT
pass out on $ext_if from 192.168.1.0/24 to any nat-to ($ext_if)

# Allow established connections
pass in on $ext_if proto tcp from any to any port ssh flags S/SA keep state

# Block all other incoming traffic from the Internet
block in on $ext_if from any to any

# Allow traffic between internal network and firewall
pass in on $int_if from 192.168.1.0/24 to $int_if keep state
pass out on $int_if from $int_if to 192.168.1.0/24 keep state

[psypro]

My understanding of OpenBSD is beginner , but it fascinates me that an AI, can write correct (?) code, just given instructions to provide NAT. And this is today, where will it be in 3 years? And for pf.conf , on OpenBSD not the most typical question ...

[psypro]

Tested the pf.conf with NAT, it works, just had to put correct ext_if and int_if for my machine

[mls64]

Originally Posted by psypro

My understanding of OpenBSD is beginner , but it fascinates me that an AI, can write correct (?) code, just given instructions to provide NAT. And this is today, where will it be in 3 years? And for pf.conf , on OpenBSD not the most typical question ...

This is indeed fascinating. Will have to try it out for some things. It might deprecate forums for answers to technical problems, for better or worse.

[Head_on_a_Stick]

AFAIUI ChatGPT is just a text completer — it selects the words most likely to come next after the prompt based on it's data set (which includes daemonforums.org, apparently). It doesn't think or reason at all and so it cannot troubleshoot in any meaningful way.

It will be very good at answering help vampire type questions though, which could be useful.