Re: rDNS Round-Robin
On Wed, Jul 8, 2009 at 5:08 PM, Mark Andrewsma...@isc.org wrote: RRsets are unordered. Software and configurations should be prepared for this. Where ordering is required it is built into the RR type. Mark On 14.07.09 14:02, Bryan Irvine wrote: I've think I've found the confirmation I was looking for in RFC 2181 section 10.2. Does this seem to confirm that round-robin PTR's are perfectly legal? yes, they are perfectly legal. However I don't know about any application that would require nor benefit of them, and I don't recommend using them. With most of applications doing reverse resolution and using its result anyhow it's still better to have always the same name... -- Matus UHLAR - fantomas, uh...@fantomas.sk ; http://www.fantomas.sk/ Warning: I wish NOT to receive e-mail advertising to this address. Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu. To Boot or not to Boot, that's the question. [WD1270 Caviar] ___ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: rDNS Round-Robin
Matus UHLAR - fantomas wrote: On Wed, Jul 8, 2009 at 5:08 PM, Mark Andrewsma...@isc.org wrote: RRsets are unordered. Software and configurations should be prepared for this. Where ordering is required it is built into the RR type. Mark On 14.07.09 14:02, Bryan Irvine wrote: I've think I've found the confirmation I was looking for in RFC 2181 section 10.2. Does this seem to confirm that round-robin PTR's are perfectly legal? yes, they are perfectly legal. However I don't know about any application that would require nor benefit of them, and I don't recommend using them. With most of applications doing reverse resolution and using its result anyhow it's still better to have always the same name... Since we're nitpicking standards here, let's be clear that there is a distinction between multiple-record RRsets, which refers to the structure of the DNS database in a particular area, and round-robin, which refers to how a multiple-record RRset is treated when being given in a response from a resolver. It is perfectly legal to have multiple PTR records in a given RRset. It is also perfectly legal for a resolver to round robin the records of a PTR RRset in its responses. Round robin behavior is not, by standards, *required* of any resolver. As Mark put it RRsets are unordered. So, if the question is: does a round-robin PTR conform to standards?, then the answer is yes. Both elements of that -- the RRset having multiple records and the resolver performing 'round robin' sorting of those records -- are optional and legal. But, if the question is: given a PTR RRset with multiple records, *must* this result in a 'round robin'? then the answer is no. No resolver is *required* to round robin anything. If it gives the RRset always in a fixed order, or randomly, or using some other algorithm, e.g. optimizing the response to place addresses that are considered closer to the requesting client at the top of the list (BIND does this via its sortlist facility), then these are all legal. Hopefully that clarifies things. - Kevin ___ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: rDNS Round-Robin
On Wed, Jul 8, 2009 at 5:08 PM, Mark Andrewsma...@isc.org wrote: In message 53d706300907081412r191946eeo5c9a66657bf8e...@mail.gmail.com, Bryan Irvine writes: On Mon, Jul 6, 2009 at 4:08 PM, Kevin Darcyk...@chrysler.com wrote: Bryan Irvine wrote: Other than to really annoy me; =A0is there a valid reason for rr rDNS? Once upon a time, BIND specifically *disabled* round-robin behavior for non-address (A/) record types. PTR RRsets, among other types, were always given in a fixed order. But, I just tried a quick test, and it appears that round-robin has been re-enabled for PTRs. Accident? I have no idea why anyone would want this behavior, except perhaps to deliberately make things annoying and the que= ry results inconsistent, in the hopes that people will prevent the creation = of round-robin PTRs in the first place. Yes but is it explicitely forbidden anywhere? RFC's maybe? I can't find anything that says you shouldn't other than the majority of people say it's dumb. (Sometimes you need an RFC to point to in order to get someone to fix something that is clearly not working correctly). ___ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users RRsets are unordered. Software and configurations should be prepared for this. Where ordering is required it is built into the RR type. Mark I've think I've found the confirmation I was looking for in RFC 2181 section 10.2. Does this seem to confirm that round-robin PTR's are perfectly legal? 10.2. PTR records Confusion about canonical names has lead to a belief that a PTR record should have exactly one RR in its RRSet. This is incorrect, the relevant section of RFC1034 (section 3.6.2) indicates that the value of a PTR record should be a canonical name. That is, it should not be an alias. There is no implication in that section that only one PTR record is permitted for a name. No such restriction should be inferred. Note that while the value of a PTR record must not be an alias, there is no requirement that the process of resolving a PTR record not encounter any aliases. The label that is being looked up for a PTR value might have a CNAME record. That is, it might be an alias. The value of that CNAME RR, if not another alias, which it should not be, will give the location where the PTR record is found. That record gives the result of the PTR type lookup. This final result, the value of the PTR RR, is the label which must not be an alias. ___ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: rDNS Round-Robin
On Mon, Jul 6, 2009 at 4:08 PM, Kevin Darcyk...@chrysler.com wrote: Bryan Irvine wrote: Other than to really annoy me; is there a valid reason for rr rDNS? Once upon a time, BIND specifically *disabled* round-robin behavior for non-address (A/) record types. PTR RRsets, among other types, were always given in a fixed order. But, I just tried a quick test, and it appears that round-robin has been re-enabled for PTRs. Accident? I have no idea why anyone would want this behavior, except perhaps to deliberately make things annoying and the query results inconsistent, in the hopes that people will prevent the creation of round-robin PTRs in the first place. Yes but is it explicitely forbidden anywhere? RFC's maybe? I can't find anything that says you shouldn't other than the majority of people say it's dumb. (Sometimes you need an RFC to point to in order to get someone to fix something that is clearly not working correctly). ___ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: rDNS Round-Robin
In message 53d706300907081412r191946eeo5c9a66657bf8e...@mail.gmail.com, Bryan Irvine writes: On Mon, Jul 6, 2009 at 4:08 PM, Kevin Darcyk...@chrysler.com wrote: Bryan Irvine wrote: Other than to really annoy me; =A0is there a valid reason for rr rDNS? Once upon a time, BIND specifically *disabled* round-robin behavior for non-address (A/) record types. PTR RRsets, among other types, were always given in a fixed order. But, I just tried a quick test, and it appears that round-robin has been re-enabled for PTRs. Accident? I have no idea why anyone would want this behavior, except perhaps to deliberately make things annoying and the que= ry results inconsistent, in the hopes that people will prevent the creation = of round-robin PTRs in the first place. Yes but is it explicitely forbidden anywhere? RFC's maybe? I can't find anything that says you shouldn't other than the majority of people say it's dumb. (Sometimes you need an RFC to point to in order to get someone to fix something that is clearly not working correctly). ___ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users RRsets are unordered. Software and configurations should be prepared for this. Where ordering is required it is built into the RR type. Mark -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: ma...@isc.org ___ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
rDNS Round-Robin
Other than to really annoy me; is there a valid reason for rr rDNS? -Bryan ___ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
Re: rDNS Round-Robin
Bryan Irvine wrote: Other than to really annoy me; is there a valid reason for rr rDNS? Once upon a time, BIND specifically *disabled* round-robin behavior for non-address (A/) record types. PTR RRsets, among other types, were always given in a fixed order. But, I just tried a quick test, and it appears that round-robin has been re-enabled for PTRs. Accident? I have no idea why anyone would want this behavior, except perhaps to deliberately make things annoying and the query results inconsistent, in the hopes that people will prevent the creation of round-robin PTRs in the first place. By the way, as a personal preference, I hate the term rDNS. Sounds like a whole different protocol, much as rwhois is a different protocol from the original whois. But this is misleading, since it's merely a different way (special naming convention and a semi-special QTYPE) of using the *same* protocol. - Kevin ___ bind-users mailing list bind-users@lists.isc.org https://lists.isc.org/mailman/listinfo/bind-users
