<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div><span>Thanks a lot . Now its very clear.</span></div><div><span></span> </div><div><span>Regards</span></div><div><span>Babu</span></div><div class="yahoo_quoted" style="display: block;"> <br> <br> <div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"> <div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"> <div dir="ltr"> <font face="Arial" size="2"> On Tuesday, 15 October 2013 6:28 PM, Steven Carr <sjcarr@gmail.com> wrote:<br> </font> </div> <div class="y_msg_container">On 15 October 2013 15:53, babu dheen <<a href="mailto:babudheen@yahoo.co.in" shape="rect" ymailto="mailto:babudheen@yahoo.co.in">babudheen@yahoo.co.in</a>> wrote:<div class="yqt7658175587" id="yqtfd22412"><br clear="none">> If I change the TTL value on the particular zone
after modifying a record<br clear="none">> in Redhat Linux BIND Caching DNS server, My Redhat bind Caching DNS server<br clear="none">> cache would be refreshed after 300 seconds but what if my backend windows<br clear="none">> DNS server is still responding to end user old record from from its cache?</div><br clear="none"><br clear="none">You need to reduce the TTL with enough time in advance to allow the<br clear="none">entry in the Windows DNS server to have fallen out of the cache and<br clear="none">been replaced with the lower TTL record.<br clear="none"><br clear="none">For example, if my zone has a TTL of 8 hours and I am planning on<br clear="none">making a change tomorrow, then today (or even yesterday) I would have<br clear="none">reduced the TTL on the zone to 15 mins. This will increase the DNS<br clear="none">traffic as the records will be requested more frequently. But it will<br clear="none">also mean that when
I make the change tomorrow the Windows DNS server<br clear="none">will only have a maximum of 15 mins with the old records. After the<br clear="none">change has been made and everything is OK you can then increase the<br clear="none">TTL back to the original 8 hours.<br clear="none"><br clear="none">Alternatively as part of the change process, ask your Windows Server<br clear="none">team to restart the DNS service after you have made your changes which<br clear="none">will cause the cache to be flushed.<br clear="none"><br clear="none">Steve<div class="yqt7658175587" id="yqtfd38891"><br clear="none"></div><br><br></div> </div> </div> </div> </div></body></html>