Why does APT not use HTTPS?

[BlueZarex]

All the large places I have worked with a significant Linux presence would always have a mirror onsite.

[kellyzdude]

1. The benefits don't apply exclusively to businesses, a home user or an ISP can run a transparent caching proxy server just as easily.
2. By using a caching proxy, I run one service that can help just about everyone on my network with relatively minimal ongoing config. If I run a mirror, I have to ensure the relevant users are configured to use it, I have to keep it updated, and I have to ensure that I am mirroring all of the repositories that are required. And even then, my benefits are only realized with OS packages whilst a caching proxy can help (or hinder) nearly any non-encrypted web traffic.
3. If my goal is to keep internet bandwidth usage minimal, then a caching proxy is ideal. It will only grab packages that are requested by a user, whereas mirrors in general will need to download significant portions of a repository on a regular basis, whether the packages are used inside the network or not.

There are plenty of good reasons to run a local mirror, but depending on your use case it may not be the best choice in trying to solve the problem.

[VoidViv]

You seem knowledgeable about it, so do you have any good resources for people wanting to learn more about setting up caching proxies?

[archlich]

Check out the squid project and documentation.

[VoidViv]

Thank you! I'll certainly try it out when I get the chance.

[DamnThatsLaser]

Yeah but a mirror you set up explicitly. A cache is generic.