Hi All

Our company use Bind9 as caching-only server serve for our customer.We encounter problem that our customers can not get ips translation of some rr records because our dns can not connect to those domain 's authorize name servers.Indeed It 's right!.We should get most current status of domain but customer do not care.They want only make it 's usable.So I have one question.How can I configure bind9 to update zone's change as soon as possible.If our dns does not get answer from domain 's authorize server It should answer customer with old values in cache as long as possible,maybe from expired records in cache if it need.

Thank

DNS is not designed to work that way you can not override the TTL of a domain, if it has expired you need to check with the authoritative server.

A way to fix your problem could be to chain your dns cache to a upstream ISP dns cache.