[dns-operations] qwest EDNS implementation error

[Tony Finch]

We received a failure report about DNS resolution failures with bea.gov.
This is due to the qwest secondary authoritative DNS servers failing to
handle unknown EDNS options correctly.

$ dig +noall +authority ns bea.gov. @a.gov-servers.net.
bea.gov.                86400   IN      NS      sauthns1.qwest.net.
bea.gov.                86400   IN      NS      sauthns2.qwest.net.

$ dig ns bea.gov. @sauthns1.qwest.net. | grep status
;; ->>HEADER<<- opcode: QUERY, status: BADVERS, id: 64086

$ dig +nocookie ns bea.gov. @sauthns1.qwest.net. | grep status
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 42545

authns1.qwest.net and authns2.qwest.net (the authoritative nameservers
for qwest.net) work correctly.

sauthns1.qwest.net and sauthns2.qwest.net (the authoritative nameservers
for bea.gov) are buggy.

Tony.
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