Configuring NTP Authentication
As of now, we have time synchronization working between R1 and an external NTP server and between R1 and R2. Our security policy, however, dictates (hypothetically, of course) that NTP traffic between hosts inside our network must be authenticated. (For additional security, we would use authentication for requests between R1 and the external NTP server as well.)
It is important to note that configuring authentication doesn’t require clients to use authentication — it merely enables them to do so. Our NTP servers will still answer requests that are not authenticated, so we’ll want to use access lists to control access as well (coming in the next lab).
Our first step in turning on authentication is to enable it on R1. Recall from above that we’re going to use the key “ThereIsTimeForEverything” (bonus points for the first person to leave a comment below telling me who that quote is from!):