Are positions in cyber warefare normally restricted to people with military experiance?
There are only a couple of parts of Computer Network Operations (CNO) that require you be active duty, and that is because those positions are actually taking part in Cyber Warfare. Outside of that, you do not even need to find a "Govt" job, as plenty of Defense Contractors have contracts withing Cyber Security for the US Gov. The one requirement you MUST have as a prior is a clearance, and typically you will need at least a DoD Secret. To get into the more sensitive realms you will need a higher clearance.
Look at companies like:
Lockheed Martin
General Dynamic
Northrop Grumman
Ball Aerospace
........I am sure there a lot more as well.
Good luck!