I ran some updates, and the name service stopped resolving. My LAN has a local nameserver to resolve domain names for virtual machines.
It turns out the /etc/resolv.conf file was overwritten, and a program called resolvconf had taken it over. resolvconf centralizes updating the resolv.conf file from several different programs that might want to change the file, like NetworkManager, ifup, ifdown, and dhclient.
There are a couple fixes. The one I chose was to replace resolv.conf.
Continue reading /etc/resolv.conf, resolvconf, NetworkManager (and systemd-resolved?) Not Working