Generated: 2022-04-24T00:00:05Z -- 2022-04-25T02:17:29Z

Disclaimer:

The following report was generated automatically. Packet loss and network issues may have introduced false positives. Please verify the results before taking action.
You can report issues with this report to: marka@isc.org

Why you should care:

Most recursive resolvers now support EDNS. Lack of EDNS support in authoritative servers results in additional queries being made as the recursive servers need to retry with plain DNS and results in slower DNS resolution.

Not answering EDNS queries is particularly bad as that is indistingishable from packet loss.

Incorrect EDNS behaviour when presented with unknown EDNS versions and EDNS options can result in DNS resolution failures and/or DNSSEC validation failures.

Failure to run fully EDNS compliant nameservers will make it hard to deploy developments like DNS COOKIES which provides mitigation against DNS amplification attacks, off path spoofing resistance, RRL advoidance and excessive resource usage.

Codes

ok - test passed.
badvers - BADVERS returned.
badversion - expected EDNS version not found.
echoed - EDNS option echoed back.
formerr - FORMERR returned.
mbz - EDNS flags echoed back.
nodo - EDNS DO flag not echoed.
noopt - OPT record not found when expected. nosoa - SOA not found when expected.
notimp - NOTIMP returned.
refused - REFUSED returned.
servfail - SERVFAIL returned.
soa - SOA found when not expected.
status - expected status code not found.
toobig - UDP response bigger that advertised buffer size.
version - expected EDNS version not found.
reset - TCP connection reset.
timeout - lookup timed out.

Summary

Of servers that responded at all:
165130 of 166852 (98.97%) responded to a EDNS version 0 query
165103 of 166852 (98.95%) responded to a EDNS unknown option
165047 of 166852 (98.92%) responded to a EDNS unknown flags
164719 of 166852 (98.72%) responded to a EDNS version 1 query
164707 of 166852 (98.71%) responded to a EDNS unknown version and option

162786 of 166852 (97.56%) of nameservers support EDNS
5910 of 162786 (3.63%) EDNS capable servers are all ok
157775 of 162786 (96.92%) EDNS capable servers support unknown EDNS versions
159096 of 162786 (97.73%) EDNS capable servers support unknown EDNS options
161876 of 162786 (99.44%) EDNS capable servers support unknown EDNS flags
154909 of 162786 (95.16%) EDNS capable servers support unknown EDNS version and options
162284 of 162786 (99.69%) EDNS capable servers support DO=1

49093 of 162786 (30.16%) EDNS capable servers return a NSID option
63937 of 162786 (39.28%) EDNS capable servers return a EXPIRE option
74856 of 162786 (45.98%) EDNS capable servers return a SUBNET option
60737 of 162786 (37.31%) EDNS capable servers return a Server EDNS COOKIE option


© 2022 Internet Systems Consortium