Domain Controller NTP

Question

We use domain controller as NTP server for all cisco devices, now i want to know is NTP Active Directory can act as SNTP also to support authentication?

Answer 1

Active Directory domain controllers can provide Network Time Protocol (NTP) services for synchronizing time across devices on a network. However, they don't natively support Simple Network Time Protocol (SNTP) with authentication in the same way that some dedicated NTP servers might.

Here’s a breakdown of key points:

1. NTP vs. SNTP: NTP (Network Time Protocol) is more accurate and designed for full network time synchronization with drift correction, while SNTP (Simple Network Time Protocol) is a simplified version primarily used for smaller devices where precision isn't critical. Most modern networked devices and domain controllers use NTP rather than SNTP.
2. Authentication: By default, Windows NTP services on domain controllers don't support NTP authentication for client devices (such as Cisco routers) via built-in options like MD5 or SHA-based hashing. If authentication is required by the Cisco devices, the domain controller's NTP service will not fulfill this out-of-the-box.
3. Options for Authentication: If your Cisco devices require NTP authentication, you would need a separate, dedicated NTP server that supports authenticated NTP. Some network environments use a hardware NTP appliance (e.g., from vendors like Meinberg) or an NTP server running on Linux that can support secure authentication. You can configure this external NTP server to sync time with the domain controller, providing an intermediary layer that supports the authentication the Cisco devices require.

In short, while an AD domain controller can act as an NTP server, it doesn't natively support authenticated SNTP for Cisco devices. Using a dedicated NTP server with authentication capabilities would be the recommended approach.

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hth

Marcin