DNS/oarc.net/txt/ednsについて、ここに記述してください。

$ dig +edns rs.dns-oarc.net txt @127.0.0.1

; <<>> DiG 9.11.1 <<>> +edns rs.dns-oarc.net txt @127.0.0.1
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 58336
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;rs.dns-oarc.net.               IN      TXT

;; ANSWER SECTION:
rs.dns-oarc.net.        60      IN      CNAME   rst.x4090.rs.dns-oarc.net.
rst.x4090.rs.dns-oarc.net. 59   IN      CNAME   rst.x4058.x4090.rs.dns-oarc.net.
rst.x4058.x4090.rs.dns-oarc.net. 58 IN  CNAME   rst.x4064.x4058.x4090.rs.dns-oarc.net.
rst.x4064.x4058.x4090.rs.dns-oarc.net. 57 IN TXT "39.110.135.12 sent EDNS buffer size 4096"
rst.x4064.x4058.x4090.rs.dns-oarc.net. 57 IN TXT "Tested at 2017-07-14 07:09:49 UTC"
rst.x4064.x4058.x4090.rs.dns-oarc.net. 57 IN TXT "39.110.135.12 DNS reply size limit is at least 4090"

;; Query time: 1282 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Fri Jul 14 16:09:49 JST 2017
;; MSG SIZE  rcvd: 279