What is refid EXT?

Hi,

One of the NTP servers I use for my own server recently has undergone changes. Now, the refid it reports is EXT. I was not able to find online as to what EXT refers to?

Does anyone know?

It’s just a four byte string, so an operator or implementer can put whatever they want.

IANA maintains a Reference ID registry: https://www.iana.org/assignments/ntp-parameters/ntp-parameters.xhtml#ntp-parameters-1
But as Ask mentioned, NTP administrators may choose other values.

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