Firewall Questions

[Christian Wolf]

Hello Jay,

Am 06.10.2014 um 21:27 schrieb Jay Ridgley:
> Folks,
>
> I have my wired network secured with ufw. However, I am wondering 
> about my laptop which is connected wirelessly via an access point. It 
> is, however, sometimes used in a more public setting. Correct me if I 
> am mistaken about it being safe on my wired network without ufw 
> running on it.

You cannot say this generally. The question here is: What is safe?

If you installed a rootkit (just an example) then it is unimportant 
which location you are in, as long as you have network access.

 From the practical perspective you will use the laptop with the access 
point connected to the LAN, right?
So if the WiFi is secured (WPA or WPA2) you can (in my opinion) consider 
it as safe as the rest of the LAN.
In fact, if someone broke your WiFi, your whole LAN would be exposed to 
this person, so it IS the same "security level".

>
> Should I run ufw on it as well?
That depends. If you hardened the services and disabled unneeded 
services (which is quite some effort), no firewall should be needed 
because you do not offer any serviced to break in.
If unsure, a firewall will give some redundancy against forgotten 
services. It will not help with kernel problems or similar things.

Here again the question is: What level of security are you looking for 
and what public settings are you thinking of?

Most of the time the problems are not incoming connections but outgoing 
connections originated by the person sitting 30cm in front of the monitor.
The iptables based filtering rules (ufw uses iptables in the background) 
do only allow to filter on a port/host/protocol basis. It does not allow 
to filter any sort of content. The best filter is to think before 
downloading and installing wild things from the net.

> If so, can I use the default configuration that is present on it? Will 
> there be a problem when it is running behind my home network as a 
> wireless device?
>
Unfortunately I have never used ufw. I use iptables directly. So I do 
not know what the defult rules are. Sorry. But I am sure they serve as a 
good starting point.

I hope I could help you even a bit.
Christian