I'm currently working on a project that has required some DNS troubleshooting, however I am fairly new to the wonderful world of networking and am at a bit of a loss as to where to begin. My specific problem probably belongs on the RaspberryPi StackExchange, so I'll avoid crossposting. Just looking for information here.

Looking for information, I was lead to the resolv.conf(5) file, resolvconf(8), systemd-resolve(1), and the beast that avahi appears to be.

My Raspi with Raspbian Buster appears to have avahi-daemon running. My Ubuntu 18.04.4 LTS has systemd-resolved AND avahi-daemon. Does resolvconf(8) (man page only on Ubuntu) coordinate the two? When is /etc/resolv.conf used/ignored?

On Ubuntu:

$ cat /etc/resolv.conf # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) # DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN # 127.0.0.53 is the systemd-resolved stub resolver. # run "systemd-resolve --status" to see details about the actual nameservers. nameserver 127.0.0.53 search telus 

On Raspbian:

$ cat /etc/resolv.conf # Generated by resolvconf nameserver 192.168.0.1 nameserver 8.8.8.8 nameserver fd51:42f8:caae:d92e::1 

Which utilities are responsible for this? I don't really understand enough jargon to sift through the man pages and differentiate all these, and I'd love an explanation of how their roles are related.