The setup allows you to use a proxy server to install and update packages in Linux Debian 12 using the apt command.

1. Create a new file with the following content:

1.2 For proxy with authorization:

touch /etc/apt/apt.conf.d/proxy.conf

Acquire::http::Proxy "http://username:password@<proxy-server-ip>:port/";
Acquire::https::Proxy "http://username:password@<proxy-server-ip>:port/";

1.3 For proxy without authorization:

touch /etc/apt/apt.conf.d/proxy.conf

Acquire::http::Proxy "http://<proxy-server-ip>:port/";
Acquire::https::Proxy "http://<proxy-server-ip>:port/";

The changes take effect immediately and do not require any action. Now all apt command requests, such as apt update, apt install, will go through the specified proxy server.