Welcome to WebmasterWorld Guest from

Forum Moderators: phranque

Message Too Old, No Replies

Understanding DNS...



3:38 am on Feb 20, 2003 (gmt 0)

10+ Year Member

I just moved several virtual sites over to a dedicated server. Easy enough until it comes to the DNS...

I've changed the DNS information on several sites within a period of one hour. However, some of the site's DNS propogates within a day some are taking longer. Why wouldn't all of them just click in around the same time?


7:31 pm on Feb 20, 2003 (gmt 0)

10+ Year Member

It all depends on the domain(s) and how each domain is set up. It also depends on the usage of the domain.

For each domain, there is the concept of a 'time-to-live' for the information contained in the domain zone. If the 'time-to-live' is set for a week, and other attributes are set up in a similar manner, there could be some DNS caches on the internet that contain the old data for up to a week.

Thus, best practice is to know about a change before the previous 'time-to-live' window starts, set the 'time-to-live' values to, say, oh about an hour or even 5 minutes, wait for the window to expire of the previous 'time-to-live', make the changes, and reset the 'time-to-live' values to your standard values.

Setting the 'time-to-live' values implies understanding the various SOA values for the domain. And, setting it too low on a "busy" domain could swamp your DNS boxes.

Hope this helps!



Featured Threads

Hot Threads This Week

Hot Threads This Month