Use the Symmetric Keys tab to add key file content so that the appliance can authenticate to your NTP servers that use symmetric key authentication.
Navigating in IPS Local Management Interface:
Navigating in SiteProtector™ Management: 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 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 your NTP servers using 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.