Dns sometimes fails using Google DNS / automatic dnssec

Thu Nov 15 17:26:24 UTC 2012

It looks like if the server has the RRSIG RR, it returns it.  For example, a
query with +dnssec will cause it to cache the RRSIG, after which it returns
it even if +dnssec not specified.

________________________________________________________________________
Jay Ford, Network Engineering Group, Information Technology Services
University of Iowa, Iowa City, IA 52242
email: jay-ford at uiowa.edu, phone: 319-335-5555, fax: 319-335-2951

________________________________________
query without +dnssec before RRSIG is cached; RRSIG not returned
________________________________________

   : dig @8.8.8.8 m1.mailplus.nl

   ; <<>> DiG 9.8.1-P1 <<>> @8.8.8.8 m1.mailplus.nl
   ; (1 server found)
   ;; global options: +cmd
   ;; Got answer:
   ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 3665
   ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

   ;; QUESTION SECTION:
   ;m1.mailplus.nl.                        IN      A

   ;; ANSWER SECTION:
   m1.mailplus.nl.         2985    IN      A       46.31.50.16

   ;; Query time: 15 msec
   ;; SERVER: 8.8.8.8#53(8.8.8.8)
   ;; WHEN: Thu Nov 15 11:22:02 2012
   ;; MSG SIZE  rcvd: 48

________________________________________
query with +dnssec; RRSIG is returned
________________________________________

   : dig +dnssec +multi @8.8.8.8 m1.mailplus.nl

   ; <<>> DiG 9.8.1-P1 <<>> +dnssec +multi @8.8.8.8 m1.mailplus.nl
   ; (1 server found)
   ;; global options: +cmd
   ;; Got answer:
   ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 58877
   ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1

   ;; OPT PSEUDOSECTION:
   ; EDNS: version: 0, flags: do; udp: 512
   ;; QUESTION SECTION:
   ;m1.mailplus.nl.                IN A

   ;; ANSWER SECTION:
   m1.mailplus.nl.         2978 IN A 46.31.50.16
   m1.mailplus.nl.         2978 IN RRSIG A 7 3 3600 20130517082302 (
                                   20121115082302 3767 mailplus.nl.
                                   WzKY2FnTbF8MOhAuDvnrPkpgskeH4aI1YByh6zBX1z1p
                                   QRo8YIcxzlSNtHv2LnKUk+0n6iIXqV77sHynHHP/Y/a0
                                   bMKYKIDuK8Gtz47AVDJaU0eX0FR8F5qqw897ClGf5ISa
                                   0njPLFVyF/NJ6hNViDYzOhhHGi58dhZmhKWFujs= )

   ;; Query time: 16 msec
   ;; SERVER: 8.8.8.8#53(8.8.8.8)
   ;; WHEN: Thu Nov 15 11:22:10 2012
   ;; MSG SIZE  rcvd: 230

________________________________________
query without +dnssec after RRSIG is cached; RRSIG returned
________________________________________

   : dig +multi @8.8.8.8 m1.mailplus.nl

   ; <<>> DiG 9.8.1-P1 <<>> +multi @8.8.8.8 m1.mailplus.nl
   ; (1 server found)
   ;; global options: +cmd
   ;; Got answer:
   ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 13524
   ;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0

   ;; QUESTION SECTION:
   ;m1.mailplus.nl.                IN A

   ;; ANSWER SECTION:
   m1.mailplus.nl.         2974 IN A 46.31.50.16
   m1.mailplus.nl.         2974 IN RRSIG A 7 3 3600 20130517082302 (
                                   20121115082302 3767 mailplus.nl.
                                   WzKY2FnTbF8MOhAuDvnrPkpgskeH4aI1YByh6zBX1z1p
                                   QRo8YIcxzlSNtHv2LnKUk+0n6iIXqV77sHynHHP/Y/a0
                                   bMKYKIDuK8Gtz47AVDJaU0eX0FR8F5qqw897ClGf5ISa
                                   0njPLFVyF/NJ6hNViDYzOhhHGi58dhZmhKWFujs= )

   ;; Query time: 17 msec
   ;; SERVER: 8.8.8.8#53(8.8.8.8)
   ;; WHEN: Thu Nov 15 11:22:13 2012
   ;; MSG SIZE  rcvd: 219