Reference: Configure Services Dialog
This is the name of the Beyond FTP installation that will provide keys to this key client. Note that key servers and clients are not the same as Beyond FTP servers and clients. A Beyond FTP client installation can act as a key server for other Beyond FTP servers. However, Beyond FTP clients cannot accept calls from other Beyond FTP clients. For this reason, a Beyond FTP client that is also a key client must go to a Beyond FTP server for its keys.