I often think I know networking pretty well. Then I'm reminded knowledge is no match for stupidity. I set up a server, on a private LAN. Then when I turned it around to be on the public LAN, it wasn't able to reach any other devices. I checked all the things, and made sure to edit the switch config to put it on the right VLAN. All good, no joy.
Then, after reloading the OS from scratch (no change), I thought to check the trunk at the *other* switch. Which blocked that VLAN. Doh!
