Record Type Number,Description,Reference
0,End of Message,"[RFC8915, Section 4.1.1]"
1,NTS Next Protocol Negotiation,"[RFC8915, Section 4.1.2]"
2,Error,"[RFC8915, Section 4.1.3]"
3,Warning,"[RFC8915, Section 4.1.4]"
4,AEAD Algorithm Negotiation,"[RFC8915, Section 4.1.5]"
5,New Cookie for NTPv4,"[RFC8915, Section 4.1.6]"
6,NTPv4 Server Negotiation,"[RFC8915, Section 4.1.7]"
7,NTPv4 Port Negotiation,"[RFC8915, Section 4.1.8]"
8-1023,Unassigned,
1024,Compliant AES-128-GCM-SIV Exporter Context,[https://chrony-project.org/doc/spec/nts-compliant-128gcm.html]
1025-16383,Unassigned,
16384-32767,Reserved for Private or Experimental Use,[RFC8915]