I'm currently experiencing an issue when connecting to a remote university Ubuntu machine using SSH (I'm using VS Code as the SSH client if it matters). Upon initial connection, it prompts me to trust the device, I do so, and I'm able to connect. However, a day later I try to reconnect and it throws an error stating that the host identity of the machine has changed.
I SSH into the machine using the DNS name. So regardless of it's IP address changing, it should always direct me to the same physical machine. Note, the machine I'm SSH'ing into is a physical desktop machine, not a VM or cluster.
So I'm curious, assuming I'm connecting to the same physical machine. Why would SSH think the remote host has changed? If the IP address of the same physical machine changes, does that result in an identity change?