Maybe someone could help me with a LTE issue here... I'm in Croatia, about 1km from the tower, -70 dBm. The (ZTE MF286) router has a MTU 1500 and MSS 1300 setti

Maybe someone could help me with a LTE issue here... I'm in Croatia, about 1km from the tower, -70 dBm. The (ZTE MF286) router has a MTU 1500 and MSS 1300 setting. I can change this setting. In Germany I have a VDSL (Telekom DSL) 100/40 MBit/s home network. A Fritz!Box 7590 is on the front and it's providing VPN access over old age cisco type xauth1+psk (aka user pass and group pass). When I try to connect in Archlinux using Networkmanager-vpnc I can connect to the German home network. But I can't ssh into any boxes in the German network. I am able to do that over Croatian DSL without issues. The adapter's MTU is 1500 and the tun0 MTU is 1412. So this works over DSL but not over TLE. When I change the adapter's MTU down to 1420 (reading libreswan's site I stumbled upon this value) I can login via ssh and seemingly also use it as it's supposed to. But then other issues arise... TLS Handshakes timing out. As if a dog is trying to chase its tail. I've canceled the TLE service subscription in the 14 day period because of that and I'm going to return the router today in 4 hours tops. This this is kind of a last straw kind of help request. Otherwise I'm stuck on a 14/1 Mbit/s VDSL connection which is painful to say the least, but at least I'm able to ssh into my German home network without problems.