Users located behind an authenticated or unauthenticated proxy connection must modify bash.bashrc and apt.conf. Both files are located in the /etc/ directory.

Edit the bash.bashrc file, as shown in the following screenshot, using a text editor to add the following lines to the bottom of the bash.bashrc file:

export ftp_proxy="ftp://username:password@proxyIP:port"
export http_proxy="http://username:password@proxyIP:port"
export https_proxy="https://username:password@proxyIP:port"
export socks_proxy="https://username:password@proxyIP:port"

Replace proxyIP and port with your proxy IP address and port number respectively, and replace user and password with your authentication username and password. If there's no need to authenticate, write only the part following the @ symbol. Save and close the file.