I tried logging into my QNAP (TS-473A running QTS 5.2.3) today and was unable to do so, either through the web interface or ssh.
After several reboots and unsuccessful login attempts I did a “basic system reset” and rebooted again. I then ran nmap to find the new IP of the QNAP and was surprised to find that the fixed IP that I had assigned to it had not changed. (Supposedly, after a basic system reset the IP should be obtained via DHCP.) Furthermore, according to nmap all ports are either closed or filtered. Screenshot below.
My next step would be an “advanced system reset”, but thought I would look for advice here before doing so.
My QNAP is not exposed to the internet. Nothing on my network has changed that would potentially cause this. And I had not made any changes to the configuration of the NAS prior to this happening.
Yes, I did the 3-sec reset, but nothing appears to have changed.
Surprisingly, the static IP that I had assigned is still being used – it never released it and pulled from DHCP. So, as far as I can tell, the the 3-sec reset did nothing.
Just closing the loop on this in case anyone else runs into a similar problem.
The issue was caused by a cron job that backs up files from my workstation to the NAS. I had rsync setup for passwordless login to the NAS.
Last week I was setting up another server on my LAN and generated a fresh key pair for passwordless ssh into the new server. That apparently led to the rsync script not being able to log into the NAS.
QNAP has a security policy will permanently ban an IP that has 6 failed login attempts. So that was why the NAS had all ports closed when I was attempting to access it from my workstation.
