On Tue, 29 Oct 2002 10:54:02 GMT, Sean Jones <sean.jones@micromedical.co.uk> 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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