Hello,
I've been using Mikrotik Chateau LTE12 for roughly more than a month and everything is super smooth so far. Today I've dug up my old Mac Mini Late 2012, wiped it clean and reinstalled the OS from scratch - to Maverics as this was the default back then. From there I've upgraded to Catalina (10.15.7) as this is the last to support Mac Mini Late 2012. Everything worked fine until up to the point when the OS was finishing the installation. This is where it gets wierd and I'm not sure it's necessarily the mini's fault, maybe some incompatibility in network features but I'm not sure how to debug further.
Just to note, this is plain clean macOS installation, running system on defaults. I've wiped everything from it before installation. My router configuration wasn't changed much since the defaults and had 0 issues before Catalina. Router is on 7.1beta4 which seems to be the latest.
The issue I'm facing is whenever I connect (either through WiFi or ETH) to my local Chateau my internet connection dies. My pings get from 50ms to seconds (up to 20-30sec) or just get lost. If I disconnect they come back to normal almost immediately. The pings either get lost totally or come in in bursts with long times when my mini is connected.
It's not any sort of device limit or network usage because even if I remove some other devices from my network, connecting the Mac Mini makes everything freeze. My local ping times (from another PC in network to router) are totally unaffected by this and are <1ms at all times.
There is nothing in the logs which would point, I don't get any information about dropped LTE connection and everything looks good. Checked my mini network config (using DHCP with DNS set to my router and from there added 8.8.8.8, 8.8.4.4), disabled WiFi. I've tried NVRAM, PRAM and SMC reset to no avail.
Just the fact of having this mini in the network makes the internet connection to be blocked. Locally it's fine.
Is this a known issue or does anybody have an idea on what else I could check? I'm ok with downgrading to Mojave of macOS, though it's bit time consuming and I wanted to try out the latest supported OS. I don't think I've seen such a thing before, I'm not a network wizard but most of the time I could manage myself out of strange situations. This one though is a puzzle, why a clean OS on a perfectly fine device would become a internet jammer.