Re: [cobalt-users] Adjusting TTL for domain change

[SM <nntp@xxxxxxxxx>]

At 23:23 07-09-2001 -0500, David Lucas wrote:
>I do believe that more problems occur the lower in the chain the dns starts 
>at.  That is if you host it yourself it then depends on each and every up 
>level to update it.  The real problem is that dns is designed to prorogate 
>down and not really up.  But we live in the real world and that means today 

That propagation is not a problem if it is administered correctly.  The DNS
cache was designed to offer redundancy.

>internic does not get everything first and then let things flow down.  We 
>just have to wait for it to get pushed to top level servers and then flow 
>back down.  If it does not get all the way up, the old start repropogating 
>down again and we start over until it gets done.  As much as sometimes I 
>would like to run dns, I have not found a real reason and leave mine with a 
>top level company. 

DNS does not get pushed to the top level servers and then flow down.   DNS
administration is not only a matter of running named.  DNS should be as
stable as possible.  Your (upstream) provider usually offers secondary and
sometimes primary DNS hosting as a free service.  You should take up the
offer of letting them be the secondary as it does not make any sense to
have the two DNS servers running on the same box.

Before getting into TTL, let's see why do we want DNS to be cached.  First
of all, it makes name lookups faster.  This means that it takes less time
for the user's box to get your IP address and establish a connection to
your site.  DNS caching also reduces the load on the user's DNS server and
your DNS server.  A higher TTL offers more stability.  If your web server
is running and your DNS servers are not responding, the user can still
reach your website if your DNS records are cache-friendly.

Regards,
-sm