Ttnctl and firewall rules

Hi,
I’ve done some scripts which are using the ttnctl for device creation and compose a last seen html page. We had to open our firewall, due to the load balancer you have at 52.178.215.58. May you give your ip range/subnet so we can write a rule that lasts more than a few hours/days (in case the load balancer is changing its address).
BR

Lukas

may I can get an answer on that question?