Nexus using sha256 authentication for NTP

GreyElf — Mon, 23 Jun 2025 18:08:40 GMT

So I can't find any real information about this, and Cisco's guide for NTP on NEXUS only uses md5. Does the Nexus OS support sha256 for NTP?

Re: Nexus using sha256 authentication for NTP

Jens Albrecht — Mon, 23 Jun 2025 19:45:34 GMT

Hello @GreyElf,

so far Cisco introduced SHA256 for NTP authentication only for IOS-XE with 17.6 while this is not supported on Nexus as of yet.

However, since NX-OS Release 10.3(3)F, NTP security is enhanced with the AES128CMAC authentication mechanism along with Type-6 encryption support for authentication keys which is in line with the RFC 8573 standards.

For configuration guidelines and limitations please refer to the NTP section of the Cisco Nexus 9000 Series NX-OS System Management Configuration Guide, Release 10.4(x).

HTH!

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Nexus using sha256 authentication for NTP

Re: Nexus using sha256 authentication for NTP