DNS Help

[Cedric Puddy]

On Wed, 18 Aug 1999, Barry Margolin wrote:

> >> Michael Voight  <mvoight at cisco.com> wrote:
> >> You've never heard of virtual servers?  Presumably his nameserver is also a
> >> web server.
> >
> >Virtual servers don't have to have different ips's.  It is an option
> >that usually has to do with the clients expected browser as some older
> >browsers did not work well with virtual hosts that didn't have their own
> >ip.
> 
> I'm fully aware of that.  I'm also aware that many web site operators wish
> to remain compatible with as many versions of browsers as possible, so they
> continue to use multiple IP addresses.  Michael Voight's question suggested
> that multiple addresses on an interface was an uncommon thing, whereas
> it's still probably the most common way to implement virtual servers.
> 
> -- 
> Barry Margolin, barmar at bbnplanet.com
> GTE Internetworking, Powered by BBN, Burlington, MA

I would agree that it is very common to have many, many
addresses on single interfaces.  On machines that I have
managed/manage it is routine to have in excess of 100
addresses per interface.  I have heard tell of some
machines running in excess of 400 addresses per interface.

Many clients that we've dealt with find that tracking
bandwidth by working backwards from per-service logs
annoying and relatively complex to implement in
comparision to simply allocating an interface to
a customer (domain), and tracking the byte-count on that
single interface.

I'm not sure about the SSL limitation Barry mentioned,
I've not done anything that would have caused me to
run across it.

One other problem with not using real IP addresses that
clients have reported is that they have trouble listing
with some search engines, apparently due to some search
engine operators treating all of those domains all
coming from one IP as some kind of attempt to flood
their database.  I haven't followed up it, so I have
little knowledge as to how true these reports may be.

Suffice to say that there are reasons to expect that
huge numbers of IPs being bound to single interfaces
is likely to continue to be a common practice.

	-Cedric


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