[Pdns-users] pdns_recursor cache and NS change

Gavarret, David david.gavarret at neufcegetel.fr
Sun May 28 16:42:28 UTC 2006

Hi all,

I just had a problem with a domain which NS servers changed. That was on a 
server running the "old" pdns_recursor 3.1-pre1, and I wanted to know if 
that was an issue of this version and if it was corrected since then (as I 
can't really test as the cache will be cleared ...) ...

The old NS servers still have the "old zone" configured (bad thing!) and so 
keep on answering with old values of 'www' if asked.
On the new NS servers, the zone has changed with another 'www' record.

But pdns_recursor's cache still have in memory old values. It seems that he 
continues caching informations from the old NS servers.

~$ dig lacentrale.fr soa
lacentrale.fr.          85024   IN      SOA     ns0.ordipat.fr. 
dns-admin.ordipat.fr. 2006032801 43200 18000 604800 86400
~$ dig www.lacentrale.fr
www.lacentrale.fr.      81803   IN      A
~$ dig @ns0.ordipat.fr www.lacentrale.fr
www.lacentrale.fr.      86400   IN      A
~$ dig @a.nic.fr lacentrale.fr ns
lacentrale.fr.          172800  IN      NS      ns.easynet.fr.
lacentrale.fr.          172800  IN      NS      ns0.easynet.co.uk.
~$ dig @ns.easynet.fr www.lacentrale.fr
www.lacentrale.fr.      7200    IN      A

Changes on the 'lacentrale.fr' zone have been done on May 11th.

Should pdns_recursor have upgraded its cache with lokking at the root 
servers for '.fr' zones ?

Thanks for your inputs,

David Gavarret 

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