-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi Jianjun,
On 03/20/2014 08:26 AM, Jianjun Ning wrote: > all, when I run command "dig @localhost . ns",I used tcpdump to > capture the DNS packets,I found that unbound query root DNS server > twice, why? The first is the root prime query, the second is the query to fetch your answer. The reason it does it twice is that the first query is run while the state machine in unbound does not perform further recursions, and the second has the state machine set to store the answer for the user. So, with the first it fetches the addresses of the root servers and the second asks one of those root servers for the answer you wanted. Realistically, the answer is stored in cache and the second query is not necessary, but there is no code there that checks the cache for contents; the cache-check code is in a different position in the implementation. I do not think that this query needs to have special-case code added to avoid the second query. Best regards, Wouter -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBAgAGBQJTKqR6AAoJEJ9vHC1+BF+Nwk8P/27k2YnH/XohNZi2n27sJJNI dUchOQeve3g809nmIQxp4ErEs609LwtKPmBC/yJL50guOqykWTGJoU0KL3lnzkTF h9J8fbMxDiPKEaEQm5zIIGijHzSn5pE+sdGVEXqna/uQGJ1HHRiF6LPt1DHCq6Tt YsjtJ8rNYTvHNwYtVQiS/d0KgR3BnftiIldlF9snjN7zPtOPgL310eRY4v3Wjfz0 y3/vojmTs7Sg4qtI7fKsgWQQfnh+IcWd3baNcXXdl5vPHMMvpkrioLjlpWhCj48S NWX3iJL6CjxKpnsYpub9qiTvpwJelv0qqVqG3QsNVn6NHR2Qv9+uWxIqbm7lvsvz 6jJPtYboY30TPDIz3MgnTR1ZWEBwBkmFKEqX73JjnCzPU5cQfg78iV9oEIJeIaro yRfP2yTebwuYUMUznFiXi58UPsEMkmxkZAtryWFppMfgRlo81jna8XdPVRGFuHE8 ylpEe4zo2cldZuRn7w6PS3TmglWkktPyPziN3+bqUSXafgUTTeLY9dLgx6omOI+w bpJY0luNA0/FJpnRfHesrzI+/CVICrTGKrgScDfsWhp59mxiwfsJnaSNzzKJWtQq dxSrYcfPfyBUyF32oY3A19XrerXdpNy/9G0PBR4HVOOSOmGwpy4dxZJ9R7cW0IgP 7Ij6k0GsvL6u7jAGZjyV =31yc -----END PGP SIGNATURE----- _______________________________________________ Unbound-users mailing list [email protected] http://unbound.nlnetlabs.nl/mailman/listinfo/unbound-users
