@Mark 65
" 1. I haven't been able to find anything suitable for remote support (not RDP) of the LogMeIn / TeamViewer type where very little is required of the user needing support - they're pretty PC illiterate. *** Any suggestions for software gratefully received *** "
Install openssh-server on their computer and login to it using ssh -X their.IP.Add.ress from your client. The -X gives you X forwarding. Then you can run GUI apps from your shell in background, e.g. try
gedit &
and it should run on their computer but display on your client.
You'll have to forward the ssh port on their firewall/router if they have a router. Good idea to install denyhosts if you do this and have good passwords. If your parents don't remember good passwords or can't input these, then their login does not want ssh remote access, sudo bash to their from your login which can have ssh access configured, so you can run their programs on your desktop if they have a GUI app which they can't congure themselves.
"2. Less solvable however is the lack of ISP support for Linux. They're utter bastards, barely support Mac and are completely unwilling to help for Linux. It's the same old windows checklist - reinstall TCP stack etc - bullshit. A router, rather than modem, should negate this bullshit entirely. If the router has a connection then from there it's your problem unless they offer total support contracts."
The router solves it entirely as you say. Everything talks Ethernet these days and can do DHCP to get an address from the router. One thing you may have to configure if you have a very old fashioned ISP is the ISP DNS server addresses. On Linux these go in /etc/resolv.conf . See point above about forwarding the ssh port, but the router should be configurable using a standard web browser on any computer on the LAN side of the router pointed at the IP of the router on the LAN, typically 192.168.1.254 , check the router documentation for this if not. Worth checking router documentation before you buy to make sure the router is controllable by you by this means and not left in an insecure state (e.g. WiFi left on with open access when you don't need it, unable to turn PnP off etc. ) without giving you ability to change this. I've seen some wretched router setups like this recently, though there may be a more suitable firmware in some cases.