nanog mailing list archives
Re: NTP question
From: Stephen Satchell <list () satchell net>
Date: Wed, 1 May 2019 18:21:04 -0700
One word of caution when using a low-priced NTP appliance: your network activity could overwhelm the TCP/IP stack of the poor thing, especially if you want to sync your entire shop to it. In the case of the networks I set up, I set up a VLAN specific to the NTP appliance and to the two servers that sync up with it. Everything else in the network is configured to talk to the two servers, but NOT on the three-device "NTP Appliance VLAN". NOTE: Don't depend on the appliance to provide VLAN capability; use a configuration in a connected switch. How you wire from the appliance to a port on your network leaves you with a lot of options to reach a window with good satellite visibility, as CAT 5 at 10 megabits/s can extend a long way successfully. Watch your cable dress, particularly splices and runs against metal. (Or through rooms with MRI machines -- I'm not joking.) The two servers in question also sync up with NTP servers in the cloud using whatever baseband or VLANs (other than the "NTP VLAN") you configure. Ditto clients using the two servers as time sources. The goal here is to minimize the amount of traffic in the "NTP Appliance VLAN". What killed one installation I did was the huge amount of ARP traffic that the appliance had to discard; it wasn't up to the deluge. Learn from my mistakes.
Current thread:
- Re: NTP question, (continued)
- Re: NTP question Brandon Martin (May 01)
- Re: NTP question Harald Koch (May 01)
- Re: NTP question Brandon Martin (May 01)
- Re: NTP question Harlan Stenn (May 01)
- Re: NTP question Harald Koch (May 01)
- RE: NTP question Keith Medcalf (May 01)
- Re: NTP question William Herrin (May 01)
- Re: NTP question Rubens Kuhl (May 01)
- RE: NTP question Keith Medcalf (May 01)
- Re: NTP question Harlan Stenn (May 01)
- Re: NTP question Stephen Satchell (May 01)
- Re: NTP question Mel Beckman (May 01)
- Re: NTP question Harlan Stenn (May 01)
- Re: NTP question William Herrin (May 02)
- Re: NTP question Chris Adams (May 02)
- Re: NTP question James R Cutler (May 02)
- Re: NTP question Harlan Stenn (May 02)
- Re: NTP question James R Cutler (May 02)
- Re: NTP question Harlan Stenn (May 02)
- Re: NTP question Eric S. Raymond (May 06)
- Re: NTP question Mel Beckman (May 01)