about cache nonexist record

[Mark Andrews]

In message <950.42549.qm at web15608.mail.cnb.yahoo.com>, "Tech W." writes:
> 
> Hello,
> 
> I have Bind-9.6.1 running on our university environment, have been using dyna
> mic update.
> 
> My question is, when other DNS query my named for a record, for example test.
> example.com, but this record doesn't exist. How long time will the remote DNS
>  cache this nonexist record?

	For up to as long as you have told it too.  The SOA minumum is
	used to set the timer.
 
> I found the problem that if this nonexist record was cached by remote DNS, ev
> en if I added the corresponding record to named zone soon, the remote DNS can
> 't find it quickly.
> 
> This is not good for dynamic update IMO, for example, I need to change a reco
> rd, then I have to do:
> 
> nsupdate delete ....
> nsupdate add ....

	Well do it in one transaction.

	nsupdate
	update delete ...
	update add ...
	send

> If the remote DNS query for this record just after 'nsupdate delete', then it
> will get nothing and cache this nonexist record for some time, even though t
> he correct record has been added. How to deal with this case?

	Not if you use nsupdate correctly.
 
> Thanks.
> 
> Regards,
> Wah.
> 
> 
>       _______________________________________________________________________
> _____________
> Access Yahoo!7 Mail on your mobile. Anytime. Anywhere.
> Show me how: http://au.mobile.yahoo.com/mail
> _______________________________________________
> bind-users mailing list
> bind-users at 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: marka at isc.org