NTP Authentication Example

1. Specify NTP Keys (Edit NTP Keys Menu on NTP s5000)

Specify your NTP keys in the following format:

Keynumber M Key ( The M stands for MD5 encryption)

eg

1 M secret
5 M RaBBit
7 M TiMeLy
10 M MYKEY

2. Specify trusted keys

In the NTP configuration menu, specify which or all of the keys specified above are trusted (ie are secure and you want to use). Any keys specified in the keys file but not trusted will not be used for authentication.

eg
1 7 10


3. The NTP server is now configured for authentication.


4. Client Configuration for Authentication.

The client needs to be configured with similar information as the server, however, you may use a subset of the keys specified on the server. A different subset of keys could be used on different clients.

eg:
Client Keys file
1 M secret
7 M TiMeLy

Client Trusted Keys: 1 7

or

Client Keys file
1 M secret
5 M RaBBit
7 M TiMeLy
10 M MYKEY

Client Trusted Keys: 7 10


Essentially authentication is used by the client to authenticate that the time server is who he says he is, and that no rogue server intervenes. The key is encrypted and sent to the client by the server where it is unencrypted and checked against the client keys to ensure a match.