I'm having issues keeping a Pi up-to-date in a customers network. The pi is there for controlling a piece of equipment, and it needs to be updated once in a while, among other things to keep backward compatibility with out servers. Only, when running sudo apt-get update, this is the result:
Ign:1 https://10.1.10.10:4100/fw_user_login.html?redirect=http://archive.raspberrypi.org/debian stretch InRelease Ign:2 https://10.1.10.10:4100/fw_user_login.html?redirect=http://raspbian.raspberrypi.org/raspbian stretch InRelease Err:3 https://10.1.10.10:4100/fw_user_login.html?redirect=http://archive.raspberrypi.org/debian stretch Release SSL: certificate subject name (*.redacted.de) does not match target host name '10.1.10.10'
Goes on like this for a couple more lines. You can already see the issue: Everything in that network is proxied through some authenticated gateway to even get internet access. This doesn't seem to be an issue for most things. Curl, for example, can do https. But for some reason, when apt does a request, apparently it gets the gateways certificate instead of the certificate from its repositories.
Does anybody have an idea how I can get the Pi to update inside that network without the customer changing anything (because, of course, they won't...)?