Re: Problem with different TTL

RFC 2136, section 7.12

   7.12. Due to the TTL minimalization necessary when caching an RRset,
   it is recommended that all TTLs in an RRset be set to the same value.
   While the DNS Message Format permits variant TTLs to exist in the
   same RRset, and this variance can exist inside a zone, such variance
   will have counterintuitive results and its use is discouraged.

So while not necessarily a 'requirement' from RFC's, BIND enforces this recommendation.  Since BIND influences what becomes 'standard accepted practice' in DNS, even though it is not a requirement it may as well be.

Rob


----- Original Message ----
> From: Aurelien Requiem <[email protected]>
> To: [email protected]
> Sent: Tue, January 5, 2010 5:00:11 AM
> Subject: Re: [Bind-dlz-testers] Problem with different TTL
> 
> Tim, Rob,
> 
> Rob, where did you get the information about the TTL please ? If you 
> could point this in a document or RFC that would be very good.
> 
> Tim, the main goal of my patch is to have dlz behave like bind. Nothing 
> more.
> As explained, with a flat file with bind, if 2 different TTLs are set, 
> only the 1st one is return for all records.
> With dlz, nothing is returned. The patch allow dlz to behave just like bind.
> 
> Thanks
> 
> PS : I know what you mean about VS and gdb ;-) Instead of gdb, try using 
> ddd :-)
> 
> Aurelien
> 
> On 5/01/2010 4:05 AM, Rob Butler wrote:
> > DNS requires all the TTL's for a RRset be the same.  A RR set is all the 
> records of the same type (like A, TXT, MX) for the same name.  Thus, if you have 
> two records with the same name and of the same type with different TTL's, your 
> data is incorrect.
> >
> > Rob
> >
> > ----- Original Message ----
> >    
> >> From: Tim Tessier
> >> To: [email protected]
> >> Sent: Mon, January 4, 2010 10:56:52 AM
> >> Subject: Re: [Bind-dlz-testers] Problem with different TTL
> >>
> >> Aurelien,
> >>
> >> I have taken a quick look at this, it appears that you are right about the
> >> db being
> >> read properly at this point. And with your modification, are you trying to
> >> avoid
> >> errors, is that the main goal? If you are trying to get the different ttls
> >> to appear
> >> then this most likely will require a patch to bind itself.
> >>
> >> I am looking deeper into this however, as I need a little bit more time to
> >> set up
> >> a mysql env to actually test this properly. Currently I have sqlite as the
> >> db, and although
> >> I believe your assumptions to be correct I would like to be sure. Also, it
> >> was easy for me
> >> to debug this little piece of code in windows using visual studio ( point
> >> and click ), please don't
> >> make fun, as I am not as familiar with gdb as I am with VS.
> >>
> >> Thanks,
> >> Tim Tessier
> >>
> >> --------------------------------------------------
> >> From: "Aurelien Requiem"
> >> Sent: Saturday, January 02, 2010 4:09 PM
> >> To:
> >> Subject: Re: [Bind-dlz-testers] Problem with different TTL
> >>      
> 
> 
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