<3BC48562-6459-4FB9-9806-731AF87FE027(_at_)network-heretics(_dot_)com>, Keith M
On Jul 24, 2011, at 11:21 PM, Mark Andrews wrote:
How do you solve the problem of hosting just "http://example.com/"
on "s1.joes-web-service.com" and not redirect everything else at
example.com? People have been complaining about this for about as
long as the web has existed.
Well, in a way, that's what NAPTR was for. All of the UR
i resolution mechanisms (equally applicable to DNS-based URIs) that =
developed and never really used grew out of the original realization =
the early 1990s that CERN could stop hosting the original web pages =
it wanted to, and there was no way to keep those links from going =
NAPTR is not defined for HTTP.
SRV is not defined for HTTP.
The problem never went away, but the DNS-based solutions were defined =
long time ago and never used.
No. It was explitly NOT defined.
Ok, fair enough. Those of us who were working on the DNS-based URI =
resolution mechanisms realized that they could be applied to http URIs =
in addition to almost anything else (NAPTR is incredibly flexible if you =
don't mind doing lots of DNS lookups). But they were never formally =
But if you really want to use DNS to do redirects for http: URIs (or for =
that matter ws: URIs or almost any other kind of URI), NAPTR was =
tailor-made to do that. SRV was not.
"_http._tcp.example.com SRV 100 0 80 <server>" is not a redirect.
The http client still issues "Host: example.com" not "Host: <server>".
If you want to do DNS level redirect of "www.example.com" to
"example.com" then NAPTR would be the way to do that and the http
client issues "Host: example.com" instead of "Host: www.example.com".
If web browers were using CNAME records correctly, i.e. as aliases,
then they would be treated as a DNS level redirect not as "return
the address of CNAME target but otherwise ignore that this is a
alias". Doing this has all sorts if implications. A lot of the
IDN issues are a direct result of HTTP clients/adminstrators abusing
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: marka(_at_)isc(_dot_)org
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