Easily zig vs kaw. It was a very active war with 80% of kaw warring. It wasn't just zig but ZAFT n IGs alliances too like protake n others.
It was ZIG vs UWF, as I referred to us. It wasn't the longest but possibly the biggest. It was as a result to ZAFT's WFTT and them disbanding the #3 lb clan. Essentially ZAFT and friends got bored. Deadly Fate the number 3 lb clan upset ZAFT somehow, and over 3 days ZAFT turned DF into nothing more but a memory. Rumours spread ZAFT would do this to others, they came to me as CR's leader, and a large group united.