On 2009-10-31 mouss wrote: > Ansgar Wiechers a écrit : >> On 2009-10-29 Phillip Smith wrote: >>> Then a) it doesn't resolve perfectly -- it should resolve both ways. >>> And b) any given IP address should only have *one* corresponding PTR >>> record, not multiple PTR's. For one, it causes problems like this. >> >> It's a perfectly valid and supported DNS feature to have multiple PTR >> records. If this causes problems, then the respective application is at >> fault, not DNS. > > Using multiple PTRs brings nothing but problems.
Which part of "then the respective application is at fault" did you fail to understand? > there is nothing bad with a setup like this: > > 192.0.2.1 PTR uranus.example.com > uranus.example.com A 192.0.2.1 > > www.example.com A 192.0.2.1 > ftp.example.com A 192.0.2.1 > blog.example.com A 192.0.2.1 > wiki.example.com A 192.0.2.1 > > ... There's also nothing wrong with a setup like this: 192.0.2.1 PTR uranus.example.com. 192.0.2.1 PTR www.example.com. 192.0.2.1 PTR ftp.example.com. 192.0.2.1 PTR blog.example.com. 192.0.2.1 PTR wiki.example.com. uranus.example.com. A 192.0.2.1 www.example.com. A 192.0.2.1 ftp.example.com. A 192.0.2.1 blog.example.com. A 192.0.2.1 wiki.example.com. A 192.0.2.1 Except that b0rken software may choke on it. Duh. And if you want to avoid multiple PTR records, there's also nothing wrong with a setup like this: 192.0.2.1 PTR uranus.example.com. uranus.example.com. A 192.0.2.1 www.example.com. CNAME uranus.example.com. ftp.example.com. CNAME uranus.example.com. blog.example.com. CNAME uranus.example.com. wiki.example.com. CNAME uranus.example.com. However, the OP's problem was not that a PTR record existed, but that a corresponding A record did *not* exist. Which is an entirely different issue. Regards Ansgar Wiechers -- "Abstractions save us time working, but they don't save us time learning." --Joel Spolsky
