Refreshing cache in other DNS servers

babu dheen babudheen at
Wed Oct 16 02:02:16 UTC 2013

Thanks a lot . Now its very clear.

On Tuesday, 15 October 2013 6:28 PM, Steven Carr <sjcarr at> wrote:
On 15 October 2013 15:53, babu dheen <babudheen at> wrote:

>  If I change the TTL value on the particular zone after modifying a  record
> in Redhat Linux BIND Caching DNS server, My Redhat bind Caching DNS server
> cache would be refreshed after 300 seconds but what if my backend windows
> DNS server is still responding to  end user old record from  from its cache?

You need to reduce the TTL with enough time in advance to allow the
entry in the Windows DNS server to have fallen out of the cache and
been replaced with the lower TTL record.

For example, if my zone has a TTL of 8 hours and I am planning on
making a change tomorrow, then today (or even yesterday) I would have
reduced the TTL on the zone to 15 mins. This will increase the DNS
traffic as the records will be requested more frequently. But it will
also mean that when I make the change tomorrow the Windows DNS server
will only have a maximum of 15 mins with the old records. After the
change has been made and everything is OK you can then increase the
TTL back to the original 8 hours.

Alternatively as part of the change process, ask your Windows Server
team to restart the DNS service after you have made your changes which
will cause the cache to be flushed.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the bind-users mailing list