Use the Symmetric Keys tab on the NTP Configuration page for the Network IPS appliance to add key file content that the appliance uses to authenticate with NTP servers that use symmetric key authentication.
Navigating in the Network IPS Local Management Interface:
Navigating in the SiteProtector™ system: select the NTP Configuration policy
Symmetric key: The server and the client use a common secret key for authentication. The advantages of symmetric key exchanges include minimal computing power usage, a relatively quick processing time, and the ability for both the sender and the receiver to encrypt or decrypt. To configure symmetric key exchange, you need the key identifiers (key IDs), key types, and key values for your NTP servers. This option is available for only NTP versions 3 and 4.
The appliance uses the configurations on this tab for all NTP servers that use symmetric key exchanges.
FIPS mode: To be FIPS-compliant, use only the cryptographic hash function SHA-1 in your symmetric key content. MD5 is not FIPS-compliant.
NIST-compliant: To be NIST-compliant, use only the cryptographic hash function SHA-1 in your symmetric key content. MD5 is not NIST-compliant.