I'm on Ubuntu 14.04 Desktop.
I have just logged into other machine (Ubuntu 14.04 Server) using ssh in one terminal. I'm still connected.
When I did scp in another terminal (opened earlier) to move a file to the same other machine, it displayed:
The authenticity of host '...' can't be established. ECDSA key fingerprint is (...). Are you sure you want to continue connecting (yes/no)? yes
I see this every first time I connect to a different machine. Why did this happen now? (I connect there everyday.) Something changed in the DHCP configuration, probably some network rearrangement? Though the IP didn't change, nor the password, for I did the scp successfully. If some configuration change did happen, was it on the few seconds between the ssh and scp? Or ssh use a different fingerprint system?
Or perhaps someone used my computer and scrambled the previously saved ECDSA key fingerprint?
Now I went to the physical server, changed the locale (to try to change some files with chinese characters in their names). The locale was changed, but it still didn't display the correct characters. I was able to rename the files, though, to wipe out the chinese characters. Now, I can't connect to the server using the browser from other computers in the same institution, like I used to do (the server's only visible inside the institution). I think the locale has nothing to do with it, but the same event that changed my previous authenticity certificate must have hidden the server from the network.