We use FQDNs that point to pools of NTP servers in our routers (example: 0.us.pool.ntp.org, pool.ntp.org, etc). Unlike nearly every other product I’ve ever used, RouterOS immediately translates this to a specific IP from the pool and saves the IP instead of the FQDN. This is really annoying because servers in the pool drop out and new ones are added over time. It maybe 6months, it maybe two years; however, inevitably, I login at some point in the future and the time and/or date is wrong. Mikrotik, please change this behavior to allow it to save the FQDN if entered so people using NTP pools can have logs and times that stays accurate.
“Server DNS Names” field is for FQDN of NTP servers.