nanog mailing list archives
Re: NIST NTP servers
From: Mel Beckman <mel () beckman org>
Date: Wed, 11 May 2016 19:10:57 +0000
No, many cell carriers run their own completely independent timing networks. I support some head-ends where they have rubidium clocks and a T1-delivered time source. They do reference GPS, and many cell sites have GPS as a backup clock (you can see their conical antennas on the very top of the tower). But most cellular providers are very protective of their time sources. They’re also typically clocking SONET networks too, which requires BITS. -mel JAshworth said:
CDMA and GSM are false diversity: both network types nodes *get their time* from GPS, so far as I know.
On May 11, 2016, at 10:54 AM, Valdis.Kletnieks () vt edu wrote: On Wed, 11 May 2016 15:36:34 -0000, "Jay R. Ashworth" said:CDMA and GSM are false diversity: both network types nodes *get their time* from GPS, so far as I know.I'll make the fairly reasonable assumption that most readers of this list have networks that span multiple buildings. If somebody is managing to figure out that you have a GPS in Building 37, and a GPS-based CDMA up on the corner of Building 3, and the *other* 4 clocks at other locations and getting close enough to all of them at the same time to conduct a successful spoofing attack, all just to move your time source a few seconds off.... ... then the fact that GPS is spoofable is probably *NOT* your biggest security problem.
Current thread:
- Re: NIST NTP servers, (continued)
- Re: NIST NTP servers Gary E. Miller (May 10)
- Re: NIST NTP servers Jared Mauch (May 10)
- RE: NIST NTP servers Chuck Church (May 10)
- Re: NIST NTP servers Gary E. Miller (May 10)
- Re: NIST NTP servers Mel Beckman (May 10)
- Re: NIST NTP servers Leo Bicknell (May 11)
- Re: NIST NTP servers Josh Reynolds (May 11)
- Re: NIST NTP servers Mel Beckman (May 11)
- Re: NIST NTP servers Jay R. Ashworth (May 11)
- Re: NIST NTP servers Valdis . Kletnieks (May 11)
- Re: NIST NTP servers Mel Beckman (May 11)
- Re: NIST NTP servers Eric Kuhnke (May 11)
- Re: NIST NTP servers Jean-Francois Mezei (May 12)
- Re: NIST NTP servers Mel Beckman (May 12)
- Re: NIST NTP servers Leo Bicknell (May 11)
- Re: NIST NTP servers Brandon Vincent (May 11)
- Re: NIST NTP servers Jon Meek (May 11)
- Re: NIST NTP servers Josh Reynolds (May 11)
- Re: NIST NTP servers Lamar Owen (May 13)
- Re: NIST NTP servers Mel Beckman (May 13)
- Re: NIST NTP servers Lamar Owen (May 13)