Debian9 upgrade

I mentioned in an earlier post that upgrading from debian8 (jessie) to 9 (stretch) solved a display mystery. (I wonder if a 3440x1440 monitor will work on this distro.) This post will record mysteries created, rather than solved.

• xsane: no devices found
  So I had to download brscan4, I forget where from... brscan4-0.4.9-1.amd64.deb
  Then I had to use brsaneconfig. Like this:
  

  sudo brsaneconfig4 -a name=mfc9340 model=MFC-9340CDW ip=192.168.1.40

• …that's it for now!

I understand that upgrading to buster (debian10) will remove python2. Since I'm a Python Dinosaur (not really analogous to my granddaughter's "Dragon Pig" concept), python3 is the new-fangled (or -fanged) thing that I don't quite feel comfortable with.

And then there was an broadband internet service change 2020-08-14
"ping" tried to use ipv6 addresses. So I did this:

collin@p64:~$ cat /etc/sysctl.d/local.conf 
net.ipv6.conf.all.disable_ipv6 = 1
collin@p64:~$ 

And after filling in DNS servers in /etc/resolv.conf, I made it not a symlink and told network manager not to update it
BUT! That was a bad idea.

[main]
plugins=ifupdown,keyfile
dns=none                       ←add
...
/etc/NetworkManager/NetworkManager.conf

Why was it a bad idea? Because I thought I could use my ISP's nameservers. But since my IP address was assigned by AT&T, my ISP's nameservers rejected all my queries. I hate rejection. So I'll stop asking.