Overview

I was once on a remote system that had apt sources blocked. I tried different mirrors. I tried https mirrors (since ubuntu mirrors by default are http). There was no hope. However, I realized I could use an apt proxy, with that proxy being my local computer I was working on. This was done from macOS, so the process includes using brew package manager.

Process

Local Computer

brew install tinyproxy

Open /opt/homebrew/etc/tinyproxy/tinyproxy.conf to edit the conf

Port 8888
Listen 127.0.0.1
Allow 127.0.0.1
Timeout 600
ConnectPort 443

tinyproxy -d -c /opt/homebrew/etc/tinyproxy/tinyproxy.conf

ssh -R 13142:127.0.0.1:8888 <RemoteSystem>

Remote Computer

On the remote, you need to pass in an option to apt-get to use a proxy address, and since you set up a reverse tunnel, you can hit that via localhost, and it should be all systems go from there.

sudo -S apt-get -o Acquire::http::Proxy="http://127.0.0.1:13142" -o Acquire::https::Proxy="http://127.0.0.1:13142" update

You can also set this option in /etc/apt so you don't need to pass -o all the time.

On the remote, confirm the listener exists:

ss -lnt | grep 13142      # expect 127.0.0.1:13142 LISTEN

Local Computer

On your Mac, confirm tinyproxy is up:

lsof -nP -iTCP:8888 -sTCP:LISTEN