I am trying to set up a web service (using the Play Framework) on an Ubuntu machine on the network. However, I am experiencing intermittent failures connecting to it, not being able to connect to it far more often than not.
One strange symptom is that these network problems affect SSH as well, and in particular the SSH host key of the machine will change, whether I am connecting to it from another Linux machine or from Windows using PuTTY. One sequence of events seems to be something like:
- After a while, I am able to SSH into the machine again.
- I access one page on the web server. It works. I try to access another page. It fails.
- Shortly thereafter, I am kicked off of my SSH connection.
- I try to SSH in - the connection can't be established.
- A while later I try to SSH in - the host key has changed. I accept the change and try to log in but I get "Access denied" in response to my password.
- A while later, I am able to SSH into the machine again.
And just now I accepted the key change, tried to log on, got disconnected before I could finish typing the password, and reconnected only to see that the key has changed again.
What could be causing the SSH host key to change? If this is a normal feature of the SSH server in response to some sort of strange behaviour, what sort of problems does this imply?