DNS Question

[Patrick Greenwell]

On Wed, 28 Jul 1999, jbp wrote:

> I apologize if this is an inappropriate post to this group. I found
> the address in a DNS Q&A  My name is Jim Peters and I have what will
> probably be a very trivial question to put to this forum.
> 
> We are in the process of moving our domains from 1 host to another.
> The problem seems to be that we are being served by both servers at
> the same time. I was told that this is because
> some ISP's have not yet updated  their DNS or they are caching DNS
> information. Is it possible to get a more defined explanation for this
> problem?

Sure. Resource records in DNS have a TTL (Time To Live) associated with
them. This means that when a request is made for a record, that record is
stored in the requestors DNS server until either the TTL expires, or until
the restart their nameserver.

When you are about to make a move, you should lower the TTL incrementally
as you get closer to the move. This prevents other people from having
potentially stale data in their cache. At this point, there is really
nothing you can do. But now you know for next time... :-)