Re: [cobalt-users] propagation..

[Jeff Lasman <jblists@xxxxxxxxxxxxx>]

At 01:53 AM 2/10/00 -0500, you wrote:

> If all of the above has been done, then it is a waiting game from there.
> 12-24 hours possibly.
> Users will get various results depending on their ISP and the status of that
> networks' cache.

Please explain what you mean by this.

Here's what it says in the O'Reilly book "DNS and BIND", by Paul Albitz & 
Cricket Liu, page 34-35:

"Name servers can't cache data forever, of course. If they did, changes to 
that data on the authoritative name servers would never reach the rest of 
the network. Remote name servers would just continue to use cached data. 
Consequently, the administrator of the zone that contains the data decides 
on a _time_to_live_, or TTL, for the data. The time to live is the amount 
of time that any name server is allowed to cache the data. After the time 
to live expires, the name server must discard the cached data and get new 
data from the authoritative name servers."

There's more to the paragraph, but that's the important part.  But even 
when I set the TTL to only 10 minutes (which I've done when I know in 
advance that I'm going to be making a change to a domain within another day 
or two; it makes for less broken connectivity in the world), I've still had 
people call me a day later to let me know that DNS hadn't propogated to 
them yet.  Anyone know why/how some nameservers can be configured to ignore 
TTL and set up their own rules?

Jeff

--
Jeff Lasman <jblists@xxxxxxxxxxxxx>