nanog mailing list archives
Re: NTP Sync Issue Across Tata (Europe)
From: "Giovane C. M. Moura via NANOG" <nanog () nanog org>
Date: Mon, 7 Aug 2023 11:36:21 +0200
So the Anycast address our devices use internally to find the closestNTP server is geo-mapped to MU.
So indeed, the pool will only send you a single NTP server in this case. GeoDNS essentially map you to mu.pool.ntp.org.You can verify what NTP servers you can expect from the Pool by querying it directly (and thus bypassing GeoDNS mappings)
$ dig mu.pool.ntp.org mu.pool.ntp.org. 62 IN A 197.224.66.40
However, the physical server is geo-mapped to the specific countries in Europe, e.g., GB, NL, FR, DE,
What really matters from GeoDNS is the IP address of your client -- the one that goes in the NTP query. So if you are using your anycast address to query, it does not matter what are the unicast addresses of your servers.
Unless the geo data ntp.org are using is inconsistent, I'd imagine the servers should be mapped to a European pool, since the physical address from which the server queries the pool is geo-mapped locally, for this specific reason.
They also use the latest Maxmind mappings, and I confirmed it experimentally. ( I think it's fully automated their update method)
/giovane
Current thread:
- Re: NTP Sync Issue Across Tata (Europe), (continued)
- Re: NTP Sync Issue Across Tata (Europe) sronan (Aug 16)
- Re: NTP Sync Issue Across Tata (Europe) James R Cutler (Aug 14)
- Re: NTP Sync Issue Across Tata (Europe) Mike Hammett (Aug 14)
- Re: NTP Sync Issue Across Tata (Europe) Mike Hammett (Aug 13)
- Re: NTP Sync Issue Across Tata (Europe) Masataka Ohta (Aug 14)
- Re: NTP Sync Issue Across Tata (Europe) Masataka Ohta (Aug 09)
- Re: NTP Sync Issue Across Tata (Europe) Jay R. Ashworth (Aug 13)
- Re: NTP Sync Issue Across Tata (Europe) Rubens Kuhl (Aug 05)
- Re: NTP Sync Issue Across Tata (Europe) Giovane C. M. Moura via NANOG (Aug 07)
- Re: NTP Sync Issue Across Tata (Europe) Mark Tinka (Aug 07)
- Re: NTP Sync Issue Across Tata (Europe) Giovane C. M. Moura via NANOG (Aug 07)
- Re: NTP Sync Issue Across Tata (Europe) Mark Tinka (Aug 07)
- Re: NTP Sync Issue Across Tata (Europe) Mel Beckman (Aug 06)
- Fwd: NTP Sync Issue Across Tata (Europe) Mel Beckman (Aug 06)
- Re: NTP Sync Issue Across Tata (Europe) goemon--- via NANOG (Aug 14)
- Re: NTP Sync Issue Across Tata (Europe) Forrest Christian (List Account) (Aug 14)
- Re: NTP Sync Issue Across Tata (Europe) Masataka Ohta (Aug 14)
- Re: NTP Sync Issue Across Tata (Europe) Forrest Christian (List Account) (Aug 14)