The device transmits fingerprints when establishing secure connections (e.g. via SSH or SSL) to the requesting remote site. On the basis of the fingerprint, the remote site can 1) uniquely identify the device and 2) verify that it has connected to the correct device, which is classified as trustworthy.
For example, if you use LANconfig to select the communication protocol SSH and you connect to a device for the first time, LANconfig produces a security query asking you whether the ssh-rsa key is known to you and whether you want LANconfig to accept this device as "known" in future.
