Cisco Wireless Lan Controller came with a certificate so the access points knew they were connecting to a real Cisco device. It had an expiry date of 10 years.

Cisco Wireless Lan Controller came with a certificate so the access points knew they were connecting to a real Cisco device. It had an expiry date of 10 years. Which occurred for us a few months ago, and then after a power failure nothing would connect, fun times. Turned out you had to upgrade to the latest firmware, then disable the security check