[nmglug] Cloudflare /etc/systemd/resolved.conf versus /etc/netplan/*.yaml; Avahi

[Tom Ashcraft]

Hey Anthony, Jared, and Eric,

I really can't thank you enough for all the insights and direct assistance 
you've recently provided in relation to my difficulties with Thunderbird and 
Cloudflare.

My interest in Cloudflare is two-fold.  

First, perhaps from NMCSLUG meetings, Anthony may remember that for some time 
I've had this notion that maybe if I got set up to use Cloudflare I would be 
to some extent bypassing Comcast's undesirable potential for abusing it's 
position as a gatekeeper.

Second, through his help with troubleshooting the quirky behavior of my 
instances of Thunderbird and IMAP servers under Kubuntu 18.04 (multiple, 
thanks to Jared), Anthony posited that symptoms indicate problems with local 
networking.  Hence, he suggested that I should reset DNS servers to Google or 
Cloudflare and try again, presumably to confirm and narrow things down. 

Whereupon I remembered old roadblocks and confusion I'd encountered some 
months back trying to get my computer to talk to Cloudflare servers.  (No 
problem with Win 10 VMs, but no recommendations seemed to apply properly to my 
particular Linux circumstances.)  So after whining to but not hearing back 
from Anthony, on whom I did not wish to overly presume, I put to NMGLUG my 
recent query for assistance with Cloudflare. 

Shortly thereafter Anthony chimed in again and very generously and quickly 
substantially reproduced, validated and overcame difficulties and concerns I'd 
had previously.  He documented his journey and solution  for me in a clear and 
comprehensive how-two (ultimately modify /etc/systemd/resolved.conf and 
restart resolved).

Also, simultaneously, Eric responded with great information about Netplan, 
something I'd never even heard of (new to Kubuntu as of 18.04; configure the 
entry in a yaml file you'll find in /etc/netplan; a link to Netplan examples). 

>From my readings, Netplan seems to imply a very elegant solution approach that 
appears to me to have potentially broader applicability, considering both of 
the interests I mentioned above.

I've tried to poke around and grok everything; and, I intend to give it all 
further study.  But obviously I'm thinking it can't hurt to submit this 
summary for further discussion and suggestions from any interested 
participants and observers before I start monkeying around again.  

I'll be working on it all as time and opportunity presents.  But at the 
moment, I'm not yet particularly confident that I possess sufficient 
comprehension of the issues so that I won't screw up something important. 

Clearly, backups of involved files are in order, etc.  It's all still pretty 
scary to me.  Thank you for patiently holding my hand and not telling me to go 
RTFMP.

Also, I thought I might ask about Avahi.  Might it also be involved; should it 
be taken into consideration?

Tom