Hey there folks,
I’m trying to figure out how to configure my UFW, and I’m just not sure where to start. What can I do to see the intetnet traffic from individual apps so I can know what I might want to block? This is just my personal computer and I’m a total newbie to configuring firewalls so I’m just not sure how to go about it. Most online guides seem to assume one already knows what they want to block but I don’t even know how/where to monitor local traffic to figure out what I can/should consider blocking.
You’ve got it backwards. A firewall blocks everything, then you open up the ports you want to use. A standard config would allow everything going out, and block everything coming in (unless you initiated that connection, then it is allowed).
So the question you should be asking, is what services do you think you’re going to be running on your desktop that you plan to allow anyone on the internet to get to?
Please stop giving bad advise. The local firewall is not the same as the public firewall and nat on the router. Your comment is incredibly misleading. You can have no Firewall and the services will not be available publicly
What are you talking about? You’re assuming that every residential router is going to have some kind of firewall enabled by default (they don’t). Sure, if OP has a router that provides a basic firewall type service then it will likely block all incoming unauthorized traffic. However OP is specifically talking about a linux-based firewall and hasn’t specified if they have a router-based firewall service in place as well so we can only provide info on the firewall they specified. And if you look at UFW, the default configuration is to allow outgoing traffic and block all but a very few defined incoming ports.
You’re also making the assumption that OP is using NAT, when that is not always the case for all ISPs. Some are really annoying with their setup in that they give a routable IP to the first computer that connects and don’t allow any other connections (I had that setup once with Comcast). In this case, you wouldn’t even need to define port-forwarding to get directly to OP’s computer – and any services they might be running. This particular scenario is especially dangerous for home computers and I really hope no legitimate ISP is still following a practice like this, however I don’t take anything for granted.
Regardless of what other equipment OP has, UFW is going to provide FAR better defaults and configurability when compared to a residential router that is simply set up to create the fewest support calls to their ISP.
You know enough to be dangerous…
Why would an ISP assign a public IP to a users device? That wouldn’t make any sense. IPs are rare and expensive so that wouldn’t waste it on you. Each customer gets one IP and that is shared for all devices via NAT.
What your describing doesn’t make any sense
You’re right, it doesn’t make any sense. And it didn’t make any sense at the time either. After setting up the router with a laptop, I moved the connection to the firewall but it refused to connect. When I finally got ahold of tech support they said the connection locks into the first machine that logs in and they had to release it so I could connect the new machine. And just like that the firewall was given a routable IP address and connected to the internet. Stupidest thing I ever heard of, but that’s how they were set up. Now this was around 15+ years ago and I would certainly hope nobody is doing that crap today, but apparently that was their brilliant method of limiting how many devices could get online at once.
no, not really. on linux that depends on the default policy of the corresponding chains, so it’s configurable. I don’t think all common distros default to reject either.
Not entirely clear but perhaps OP is talking about blocking unwanted outgoing reqjests? E.g. anti-features and such since they mention traffic from their apps.
Possibly? The way I read it, it sounded like OP wasn’t really even sure what a firewall does.