Ubuntu Mirror Installation
To Change Mirror Manually You have to change your mirror address in /etc/apt/sources.list
After that run the apt update command
Bardia Moshiri Mirror in Iran
20.04:
Ubuntu Main Repositories
deb http://ubuntu.bardia.tech/ubuntu/ focal main restricted universe multiverse
deb-src http://ubuntu.bardia.tech/ubuntu/ focal main restricted universe multiverse
Ubuntu Update Repositories
deb http://ubuntu.bardia.tech/ubuntu/ focal-updates main restricted universe multiverse
deb-src http://ubuntu.bardia.tech/ubuntu/ focal-updates main restricted universe multiverse
18.04
Ubuntu Main Repositories
deb http://ubuntu.bardia.tech/ubuntu/ bionic main restricted universe multiverse
deb-src http://ubuntu.bardia.tech/ubuntu/ bionic main restricted universe multiverse
Ubuntu Update Repository
deb http://ubuntu.bardia.tech/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://ubuntu.bardia.tech/ubuntu/ bionic-updates main restricted universe multiverse
For other distros change OS Codename after mirror URL. For example 16.04 is xenial which should be replaced with bionic or focal