Connectivity
Connectivity and managing Your Comcast Business network
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Topher
Visitor

NTP servers

Hello gang,

 

Does Comcast run any public/customer-facing NTP servers?
If so, what are their locations and strata?

 

Certainly, I can use servers on other nets, but it's always nice to have one topologically near and relatively symmetrically consistent.

 

Thanks!

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Community Manager
Community Manager

Re: NTP servers

Thanks for taking the time to reach out to us through our Business Forums. I would love to address your questions regarding NTP servers. Can you please tell me what you would be using them for? -Comcast_Michelle

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Topher
Visitor

Re: NTP servers

Thank you for the rapid response, Michelle.
Fair question.  I would be pointing my own local NTP server to it/them, and then serving my own network from my server.
Your server(s) will therefore only see queries from my one highest stratum server.

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Community Manager
Community Manager

Re: NTP servers

Thank you so much for taking the time to reach back out to us. We do not have NTP servers available for customers use to connect to at this time for this purpose. -Comcast_Michelle

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anastrophe
New Member

Re: NTP servers

Most - but not all - of the following IP addresses respond to NTP client requests for time or peer connections.

 

root@ dev ~ # dnsip time.comcast.com
68.87.102.164 68.87.31.6 68.87.31.7 96.114.29.6 69.252.204.141 69.252.204.109 68.87.51.132 69.252.204.140 68.87.66.59 68.87.66.58 96.114.29.7
root@ dev ~ # dnsip time.xfinity.net
165.160.13.20 165.160.15.20
root@ dev ~ # dnsip time.xfinity.com
69.252.204.140 96.114.29.7 68.87.51.132 68.87.66.59 96.114.29.6 68.87.66.58 69.252.204.141 69.252.204.109

 

They appear to be regionally distributed, so you'll want to look up the IP addresses and find the ones closest to you (wolframalpha is remarkably good at nailing that down).

 

I'd thought that the time.comcast.net address might be the 'mothership', having 123 as the last octet, same as the NTP port, but not so.

 

I randomly checked a few as peers, and they all came up as stratum two.

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Official Employee

Re: NTP servers

Thank you for providing this feedback! Do you have any additional questions or concerns that I can help with this evening? -Comcast_Gabe

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