Ok FurryNutz,
The problem has been identified and solved, thanks to you.
I definitely followed what was happening when adding devices, one by one. Everything was fine until I plug one of my "CPL" (Ethernet through the electric wired network in the house)... Then I lost all of my DNS fixed IPs. Just went nuts with that.
Then I thought about one thing, the provider gave me 2 routers. The Ubee, which is just a modem, no router, on which I connect the 868L, and a new one recently which serves as a TV Box and Voip.
Then I thought "would that stupid one also serve as a router and DHCP server, conflicting with the 868L? As soon as I disconnected it, my reserved IPs were back and fine.
So I turned that one as "client" only to get TV and connected the phone on the Ubee (which also has a phone jack) and voilą. Problem solved.
The only thing I had was my AppleTV daisy chained to the router. Then the AppleTV was not connected to the Internet anymore but I finally switched it to WiFi, connected to the 802.11n/802.11ac 5GHZ hotspot and it works like a charm, even in FullHD 1080. I'm in the house basement but still, no hiccups.
Was just wondering whether it was possible to tell the 868L to ignore the other router? Any idea? But it's NOT important, everything works fine now and on my MacbookPro, I'm now surfing at 230Mbs... Wow!
Again, 1000x thanks for your patience and help. You really did lead me to the methodological investigation
