(Welcome to “Note to Self”, a new series of hopefully short posts where I attempt to remind my future self of the correct way of doing things I often sometimes get wrong, even after decades.)
The correct syntax for specifying nameservers in /etc/resolv.conf is:
not:
Worse, the system won’t complain; it’ll just ignore those entries, so you may wonder for a while about why name resolution is not working.
Of course, when adding an entry to an existing file, you probably won’t make this basic mistake, as any current entries will use the correct “nameserver” syntax. But when creating a new file from scratch… not that it happened to me yesterday, oh no. 🙂