Time server for Starlink users

Setup: I don’t use OpenWRT as my router. I use it for 5 WAPs behind a pfSense router with Starlink internet.

I was and still do some beta testing for Starlink. A few months ago I was made aware that the Stratum 1 GPS based time server that was always present on Starlink systems was now available to users at the local address 192.168.100.1. It is not working with the current pfSense but I’ve got folks from the Network Time Foundation engaged with the pfSense team/forum and it looks like an official fix from both ends is eminent.

However, it does seem to be working with OpenWRT. If you have Starlink, give it a try.

root@Poolhouse:~# ntpdate 192.168.100.1
31 Mar 08:39:32 ntpdate[3577]: adjust time server 192.168.100.1 offset +0.000058 sec


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I’m intrigued and confused.

How does Starlink hijack localnet? Is it some sort of double-NAT situation where your upstream gateway IP is in 192.168.100.0/24?

I assume 192.168.100.1 is the Starlink NTU default IP address (perhaps it's also fixed and not changeable).

In which case it's likely just exposing some of the GPS time-sync information (i.e. the same as having an ntpd service backed by a GPS receiver).

Yes, but it is a bit different. The local workings in the actual Starlink dish are reachable at the 192.168.100.1 address. Their router provides a 192.168.1.0/24 network to the user. Depending on which base station (POP) you are assigned to you get another outward facing IP for things like DynDNS. This changes depending on their internal loading and new POPs coming online. I’ve been bounced all over the west coast. I run the Starlink router in full bypass mode to a Netgate Appliance running pfSense+ and just use OpenWRT for WAPs about my house, shop and property. But if you need, you can get a static IP from Starlink in a priority plan. Because I was an early beta and have done some testing for them (been through every generation), my address is from a DHCP pool but is statically mapped based on the dish. It does change when they move my POP.

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Thank you for the detailed explanation, @Cosmo ! No experience with Starlink myself so it was helpful to understand this.