Assuming it is a DNSSEC aware recursive server it asks the COM servers if it hasn’t cached it as part of the referral process.
[beetle:~/git/bind9] marka% dig ds example.com @a.gtld-servers.net ; <<>> DiG 9.13.1+hotspot+add-prefetch+marka <<>> ds example.com @a.gtld-servers.net ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 57511 ;; flags: qr aa rd; QUERY: 1, ANSWER: 6, AUTHORITY: 13, ADDITIONAL: 27 ;; WARNING: recursion requested but not available ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;example.com. IN DS ;; ANSWER SECTION: example.com. 86400 IN DS 31589 8 1 3490A6806D47F17A34C29E2CE80E8A999FFBE4BE example.com. 86400 IN DS 31589 8 2 CDE0D742D6998AA554A92D890F8184C698CFAC8A26FA59875A990C03 E576343C example.com. 86400 IN DS 43547 8 1 B6225AB2CC613E0DCA7962BDC2342EA4F1B56083 example.com. 86400 IN DS 43547 8 2 615A64233543F66F44D68933625B17497C89A70E858ED76A2145997E DF96A918 example.com. 86400 IN DS 31406 8 1 189968811E6EBA862DD6C209F75623D8D9ED9142 example.com. 86400 IN DS 31406 8 2 F78CF3344F72137235098ECBBD08947C2C9001C7F6A085A17F518B5D 8F6B916D ;; AUTHORITY SECTION: com. 172800 IN NS b.gtld-servers.net. com. 172800 IN NS a.gtld-servers.net. com. 172800 IN NS e.gtld-servers.net. com. 172800 IN NS h.gtld-servers.net. com. 172800 IN NS k.gtld-servers.net. com. 172800 IN NS i.gtld-servers.net. com. 172800 IN NS j.gtld-servers.net. com. 172800 IN NS c.gtld-servers.net. com. 172800 IN NS f.gtld-servers.net. com. 172800 IN NS l.gtld-servers.net. com. 172800 IN NS d.gtld-servers.net. com. 172800 IN NS m.gtld-servers.net. com. 172800 IN NS g.gtld-servers.net. ;; ADDITIONAL SECTION: b.gtld-servers.net. 172800 IN A 192.33.14.30 b.gtld-servers.net. 172800 IN AAAA 2001:503:231d::2:30 a.gtld-servers.net. 172800 IN A 192.5.6.30 a.gtld-servers.net. 172800 IN AAAA 2001:503:a83e::2:30 e.gtld-servers.net. 172800 IN A 192.12.94.30 e.gtld-servers.net. 172800 IN AAAA 2001:502:1ca1::30 h.gtld-servers.net. 172800 IN A 192.54.112.30 h.gtld-servers.net. 172800 IN AAAA 2001:502:8cc::30 k.gtld-servers.net. 172800 IN A 192.52.178.30 k.gtld-servers.net. 172800 IN AAAA 2001:503:d2d::30 i.gtld-servers.net. 172800 IN A 192.43.172.30 i.gtld-servers.net. 172800 IN AAAA 2001:503:39c1::30 j.gtld-servers.net. 172800 IN A 192.48.79.30 j.gtld-servers.net. 172800 IN AAAA 2001:502:7094::30 c.gtld-servers.net. 172800 IN A 192.26.92.30 c.gtld-servers.net. 172800 IN AAAA 2001:503:83eb::30 f.gtld-servers.net. 172800 IN A 192.35.51.30 f.gtld-servers.net. 172800 IN AAAA 2001:503:d414::30 l.gtld-servers.net. 172800 IN A 192.41.162.30 l.gtld-servers.net. 172800 IN AAAA 2001:500:d937::30 d.gtld-servers.net. 172800 IN A 192.31.80.30 d.gtld-servers.net. 172800 IN AAAA 2001:500:856e::30 m.gtld-servers.net. 172800 IN A 192.55.83.30 m.gtld-servers.net. 172800 IN AAAA 2001:501:b1f9::30 g.gtld-servers.net. 172800 IN A 192.42.93.30 g.gtld-servers.net. 172800 IN AAAA 2001:503:eea3::30 ;; Query time: 18 msec ;; SERVER: 192.5.6.30#53(192.5.6.30) ;; WHEN: Thu Feb 21 16:39:15 AEDT 2019 ;; MSG SIZE rcvd: 1088 > On 21 Feb 2019, at 4:19 pm, rams <brames...@gmail.com> wrote: > > Greetings.....! > > how does recursive resolver get the information for a zone example.com in > below setup when > > example.com has DS records in .com > > .com is tld zone > example.com is sld zone > > Regards, > Ramesh > _______________________________________________ > Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe > from this list > > bind-users mailing list > bind-users@lists.isc.org > https://lists.isc.org/mailman/listinfo/bind-users -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org _______________________________________________ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
