DNS.Message.EDNS0.OptionCode (DNS v0.4.1)
View SourceDNS EDNS0 Option Codes (OPT)
0 Reserved [RFC6891](https://datatracker.ietf.org/doc/html/rfc6891)
1 LLQ Optional [RFC8764](https://datatracker.ietf.org/doc/html/rfc8764)
2 Update Lease Standard [RFC-ietf-dnssd-update-lease-08]
3 NSID Standard [RFC5001](https://datatracker.ietf.org/doc/html/rfc5001)
4 Reserved [draft-cheshire-edns0-owner-option]
5 DAU Standard [RFC6975](https://datatracker.ietf.org/doc/html/rfc6975)
6 DHU Standard [RFC6975](https://datatracker.ietf.org/doc/html/rfc6975)
7 N3U Standard [RFC6975](https://datatracker.ietf.org/doc/html/rfc6975)
8 edns-client-subnet Optional [RFC7871](https://datatracker.ietf.org/doc/html/rfc7871)
9 EDNS EXPIRE Optional [RFC7314](https://datatracker.ietf.org/doc/html/rfc7314)
10 COOKIE Standard [RFC7873](https://datatracker.ietf.org/doc/html/rfc7873)
11 edns-tcp-keepalive Standard [RFC7828](https://datatracker.ietf.org/doc/html/rfc7828)
12 Padding Standard [RFC7830](https://datatracker.ietf.org/doc/html/rfc7830)
13 CHAIN Standard [RFC7901](https://datatracker.ietf.org/doc/html/rfc7901)
14 edns-key-tag Optional [RFC8145](https://datatracker.ietf.org/doc/html/rfc8145)
15 Extended DNS Error Standard [RFC8914](https://datatracker.ietf.org/doc/html/rfc8914)
16 EDNS-Client-Tag Optional [draft-bellis-dnsop-edns-tags]
17 EDNS-Server-Tag Optional [draft-bellis-dnsop-edns-tags]
18 Report-Channel Standard [RFC9567](https://datatracker.ietf.org/doc/html/rfc9567)
19-20291 Unassigned
20292 Umbrella Ident Optional [https://developer.cisco.com/docs/cloud-security/#!integrating-network-devices/rdata-description][Cisco_CIE_DNS_team]
20293-26945 Unassigned
26946 DeviceID Optional [https://developer.cisco.com/docs/cloud-security/#!network-devices-getting-started/response-codes][Cisco_CIE_DNS_team]
26947-65000 Unassigned
65001-65534 Reserved for Local/Experimental Use [RFC6891](https://datatracker.ietf.org/doc/html/rfc6891)
65535 Reserved for future expansion [RFC6891](https://datatracker.ietf.org/doc/html/rfc6891)