Separatist formed the Drir organization which brought 1 planet and it's two moons under control. Later 2 other colonies joined the Drir and formed the Drir federation. The rest of humanity imposed strict sanctions, basically cutting of the federation. It in turn completely sealed itself of completely. After 15 years the federation started expanding and taking over several colonies with much bloodshed. This let to the earth-Drir war. After 3 years of fighting the Drir have retreated to 6 heavily fortified star systems and a truce was established.
The symbol on the flag depicts that original planet and it's two moons. The white background symbolizes the security inside the Drir federation while the red bars symbolize the threat from the outside.