the prod server is pretty "closed" and I need to open up for FIND.
Is it enough to open
http://es-api01.episerver.com/xxx_key which is IP 126.96.36.199
on a production server? or can it vary somehow?
We can never gurantee that we will not change the IP behind http://es-api01.episerver.com. So we might in the future change that for various reasons. Nothing planned as of now but we do not recommend using the IP.
It also seems that you need to open up for access to dl.episerver.net. If not, I end up with this error:
ERROR EPiServer.Find.UI.Helpers.ExternalResourceHelper: Could not fetch https://dl.episerver.net/version.json
Same error here. How could we possibly open up for dl.episerver.net if it does not have a fixed ip or range?
What is that used for anyway? The Find client knows its own version and it shouldn't be possible that the Find cluster uses a lower version than the client.
If configuration for this is needed it should be in the documentation.