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