I noticed a problem with Dash Central yesterday (it could not fetch data from any of my masternodes) and on dashninja.pl there were also a few closed ports on my masternodes. So i ended up doing some Linus updates and rebooting my VPS server. That fixed the Dash Central not being able to fetch data problem, but even today i am still seeing some closed port issues on dashninja.pl eventhough my masternodes are working fine.
So i have a feeling that dashninja is currently providing some false positives on the closed port status of certain masternodes and i also feel a server reboot could possibly be enough, now that the spork was used to trigger the network to lock again ?
I did not noticed any 'IO error ... Too many open files' error in my debug logs yesterday or any other problems in my debug logs, so this could be totally unrelated.
Just keep in mind that dashninja.pl is not always accurately showing the port status of the masternodes.
I do wonder if a server reboot would be enough to clear the 'IO error ... Too many open files' error that is being referenced.
See also this post on Reddit :