On Tue, 29 Oct 2002 10:54:02 GMT, Sean Jones <[EMAIL PROTECTED]> said: > Why would MS (or anyone for that matter) want multiple pointer records when > one will suffice. My thoughts revolved around clustered servers, .net & etc In > short the Microsoft-verse.
You're close. You'd want this for multihomed servers, so a PTR query works
as you'd expect. Consider this case:
www.big-corp.com A 10.0.0.10
A 192.186.10.10
mail.big-corp.com A 10.0.0.10
A 172.16.23.10
Then you'd want to have PTRs as follows:
192.168.10.10 PTR www.big-corp.com
172.16.23.10 PTR mail.big-corp.com
(and then the magic)
10.0.0.10 PTR www.big-corp.com
PTR mail.big-corp.com
If you don't have 2 PTR records for that last, you can get into the situation
where a system will look up the A record for www, get the IP address, then
do a PTR to sanity-check, get back only the mail. address, and get upset.
Having both PTR records means that you'll be able to find one to match to
the original hostname either way...
> In reality it doesn't matter two hoots what MS do, they will still have to
> inter-operate with the rest of the Internet per se, unless you believe the
> scare mongering that with .Net MS want to make a corporate Internet which they
> control.
Note that Microsoft is being very careful to fight the .Net war at the
application level and leave transport and lower alone, simply because they
know they need to interoperate.
> Thinking along a bit more, setting the routers shouldn't be a big issue,
> after all Cisco have been producing routers IPv6 capable for a fair while now,
> so surely they could incorporate multiple PTR records within the routers
> capability?
Routers don't have anything at all to do with PTR records. What I said
was that if a company wanted to block all access to Microsoft's servers,
they'd have to keep continual track of all the IP addresses in use - which
can be interesting if round-robin DNS or other similar things are in use.
--
Valdis Kletnieks
Computer Systems Senior Engineer
Virginia Tech
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