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@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