@ pato: Thanks for your comment
No, still the same router (connect box from UPC) and it worked on it just fine, no special settings needed - until this September, then the router started malfunctioning, restarting randomly, dropping wifi, etc…. my guess is that this happens due to some “maintenance” from either UPC or Sunrise (maybe due to UPC to Sunrise migration)…
So, if that has been the case for years, ho is it so it worked and it stopped without changes on my side?
Anyway, this is a very simple feature and every router can do it, even my first one, which is almost 20 years old… 🙁
I have read the posts on it, howevem there is not concrete technical response to them - I might have missed some…
All I found says, there was never this feature and it is on feature list… Some had similar problem to mine, i,e, it worked just fine and stopped recently - so, I would like to get an explanation.