6.6 to 7.3 - all in between - never EVER reliable. Ports 7 and 8 - an AP on each = trunked 1 will work, 1 won't. 2 will work... power outage - 1 will work, 1 won't - but reversed this time. Can SSH to AP - it can't ping FTD. Reboot - now that one CAN...