[SOLVED] SSH rsync error

I just wanted to post this as there may be others experiencing the same issue. 8)

I have two NAS devices, a PRO and an ULTRA, on separate locations and I am doing an rsync between the devices over the Internet. To do this safely, I enabled SSH on the ULTRA (pretty cool and useful plugin RSync over SSH Enabler). This worked great for quite some time and then, all of a sudden, my main NAS started complaining with the following messages:

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: POSSIBLE DNS SPOOFING DETECTED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ The RSA host key for <host> has changed, and the key for the according IP address <IP> is unknown. This could either mean that DNS SPOOFING is happening or the IP address for the host and its host key have changed at the same time. @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be eavesdropping on you right now (man-in-the-middle attack)! It is also possible that the RSA host key has just been changed. The fingerprint for the RSA key sent by the remote host is <fingerprint>. Please contact your system administrator. Add correct host key in /root/.ssh/known_hosts to get rid of this message. Offending key in /root/.ssh/known_hosts:15 Keyboard-interactive authentication is disabled to avoid man-in-the-middle attacks.

The way to solve this is to SSH into the NAS device(s) (Enable Root SSH Access) and rename all the "known_hosts" files (my system had several). You can delete the files, but renaming them will give you some piece of mind ,just in case. Next time your backup jobs start up again, this file will be re-created automagically and correctly.

How to find these files?

find / -name known_hosts -print

then you rename them as follows, using each file found.

mv path_and_file path_and_file.OLD

In other words, if a file that was found is

/root/.ssh/known_hosts

you would type

mv /root/.ssh/known_hosts /root/.ssh/known_hosts.OLD

GOOD LUCK!