The NDS server has been inaccessible from the outside for some time. I checked the port forwarding settings and they look correct, so this might have something to do with the router. Alastair ordered it some time ago so perhaps it is in.
In trying to troubleshoot this issue, I noticed that---when accessing the data with DV from within the network---I couldn't look at data from more than a few minutes ago. While I was on the diagnostics MEDM screen, I noticed that the FB indicators flashed red every few minutes and then went back to normal. This is just about the right timescale to explain why only very recent data is viewable.
In trying to troubleshoot this issue, I unacquired some channels (in case the DAQ rate was too high, which I don't think it was) and tried restarting daqd in the usual way. Then all hell broke loose, and the process wouldn't stay running for more than about a minute, during which the indicator was red all for except a few brief green flashes (with errors).
I enlisted Frank's help. We tried restarting the front end and then the diagnostic indicated no sync signal. Finally, we decided to reboot fb0 to see if that helped. While booting, it found an error and forced a disk check, which is probably still running now.
I will try to get it running again in the morning, and then see if I can get the new router swapped in and get NDS visible.