...
However, if you SSH to another computer with your userid and password instead of using the public keys, then the password is transmitted over the encrypted SSH tunnel, and the other machine can login and save the password. Then the saved password can be used to create connections from the remote machine to other systems in the local network.
Components that run as SYSTEM, especially SQL Server and everything associated with Hyper-V, can only access local resources. For this reason, SQL Server can only Backup and Restore databases to local files, and Hyper-V can only Export and Import VMs or connect ISO images that are on local disks.
Most of the time, however, “impersonation” is a term associated with special applications. It is used in cases where an authorized application performs an operation on behalf of a remote user while switched to the SID of that remote user. This is a complicated programming technique outside the scope of this article.
...