In article <mailman.727.1372684591.20661.bind-us...@lists.isc.org>, Matus UHLAR - fantomas <uh...@fantomas.sk> wrote:
> >> >In article <mailman.710.1372442831.20661.bind-us...@lists.isc.org>, > >> > Charles Swiger <cswi...@mac.com> wrote: > >> >> Certainly. Various software performs what's called a double-reverse > >> >> lookup > >> >> to confirm that the A and PTR records match. > > >In article <mailman.718.1372672345.20661.bind-us...@lists.isc.org>, > > Matus UHLAR - fantomas <uh...@fantomas.sk> wrote: > >> He apparently meant exactly the same. Also calles FcRDNS - "forward > >> confirmed" or "full circle" reverse DNS. > > On 01.07.13 14:11, Sam Wilson wrote: > >OK. So what Mr. Swiger refers to is not relevant - it's no reason to > >add PTR records. > > Yes, it is. > > "Various software performs what's called a double-reverse lookup to confirm > that the A and PTR records match." > > It means that various software checks your PTR and then A (or maybe > AAAA) records, and can fail if eny of them is not found ot rhe latter result > doesn't match the original IP address. There may be a subtle language thing going on here. I read the original post above as saying, literally, "you need PTR records because various software tries to match A and PTR records". It doesn't say "you need PTR records because some systems require PTR records (and if you have them they will also need to match the A records)". PTR records are nice but they aren't a general requirement. Can anyone here give examples of the types of various software that will not operate without a PTR record? > Now that IS a reason to add PTR for IP address, and they must point to > hostnames that point to the same IP. I agree that if PTR records exist then they should match an A record. My experience (and IIRC correctly the word of several RFCs) is that PTRs are not required for most things to work. Sam -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336. _______________________________________________ Please visit https://lists.isc.org/mailman/listinfo/bind-users to unsubscribe from this list bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users