![Arista C-250 Quick Start Manual Download Page 18](http://html.mh-extra.com/html/arista/c-250/c-250_quick-start-manual_2970805018.webp)
Appendix A: AP-Server Mutual
Authentication
The AP-server communication begins with a mutual authentication step in which the AP and server authenticate
each other using a shared secret. The AP-server communication takes place only if this authentication succeeds.
After the authentication succeeds, a session key is generated. From this point on, all communication between
the AP and server is encrypted using the session key.
The AP and server are shipped with the same default value of the shared secret. Both the server and the AP have
CLI commands to change the shared secret.
Note: After the shared secret (communication key) is changed on the server, all APs connected to the
server will automatically be set up to use the new communication key. You must manually configure the
new communication key on an AP if it is not connected to the server when the key is changed on the
server.
Note: Although the server is backward compatible—that is, older version APs can connect to a newer
version server—this is not recommended.
17