Symmetricom S100 manual NTP Authentication, Authentication NTP

detected. Therefore, the Reference Timestamp will indicate the time at which the timing signal was lost. When the timing signal returns, the Reference Timestamp will be updated.

Originate Timestamp

This is the local time at which the request departed the client host for the service host, in 64- bit time stamp format.

Receive Time stamp

This is the local time at which the request arrived at the service host, in 64-bit time stamp format.

Transmit Time stamp

This is the local time at which the reply departed the service host for the client host, in 64-bit time stamp format.

Authenticator

This field is used to hold a cryptochecksum if authentication has been enabled. Refer to the next section for more information about this mechanism.

Autokey

This field contains various autokey parameter requests and responses if autokey is enabled for the association. These parameters can include signatures, certificates, or other data.

NTP Authentication

NTP authentication enables an NTP client to ensure two things: that the time stamp received has come from a trusted source, and that it has not been modified in transit. Because Symmetricom has extended the authentication method, you can use it to deny service to unauthorized clients who submit NTP time stamp requests.

The NTP protocol includes space for two variables related to authentication: an authentication key identifier field and a cryptochecksum field.

Authentication: NTP v3

The NTP client can operate with both non-authenticated and authenticated servers. This approach uses symmetric-key cryptography. Thus, keys and key identifiers are determined in advance and distributed in traditional ways.

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