Both.
Yes, but there are a lot of Free and Open Source solutions.
Yes, it can. But the caching part of squid is useless here.
Nothing to do with private videos.
I realize i missed a use case in the previous response.
Imagine your server is on a private network (at your home if self-hosting, in a private network in the datacenter, …). So, there might be some computers accessible only by private IP. So, a malicious actor could try to send request to these IP using the various Peertube functionnalities which sends request.
For example by entering http://192.168.0.23/whatever/something in the import functions.
Or even if there is no private network, maybe you have some monitoring services that are accessible on localhost on your Peertube server. For example, tools like monit could listen http request on a localhost port.
This is why it is suggested to install a proxy. A proxy is just a little server that forwards http(s) requests.
The idea is to either:
- install a proxy on a separate computer that does nothing else (and has no local service, and no private network access)
- or install a proxy on the Peertube server, that will ensure there is no request to localhost or private IP (this means it has to be configured so)
There is no one-for-all answer to the question « how do i install a proxy for Peertube ». It really depends on your setup. It is an sys admin job to evaluate the risk, and choose the solution.
If your Peertube is the only service on the server, and is not part of a local/private network, you can probably ignore this step.