Re: Some ISP's having problem with my www subdomain

In article <c1mcbk$1un8$1@sf1.isc.org>,
Jeff Lasman <blists@nobaloney.net> wrote:

> Perfect? Will maybe to them.
>
> For lucidsage.com they return a list of 20 congtiguous A records, all on
> the same network.

That's because the zone name can't be a CNAME record, so they're forced
to hard-code Akamai's IP addresses (with potential problems if Akamai
renumbers their servers).

> For www.lucidsage.com they return two CNAME records, one to
> geo.premiumservices.yahoo.com, and one to premium.geo.yahoo.akadns.net
> (akami?).

It's not really two CNAME records, it's a chain of CNAMEs, which is
permitted. This looks like a reasonable, modular setup -- if Yahoo
changes the company that they contract with to host their "Premium
Services", they don't have to tell all their customers to update their
CNAME records. The customers point their aliases to something in the
yahoo.com domain, and Yahoo points that name to the hosting vendor's
domain.

There's extra overhead in the chain of CNAMEs. But since Yahoo and
Akamai are widely used hosting companies, I expect that these entries
will often be found in caches, so the overhead is minimal.

--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA