Re: Load balancing/Multiple CNAME's (Was: Re: Beyond DNS...)

[Studded <Studded () san rr com>]

Daniel Reed wrote:

> First of all, I would have a CNAME along with extra information 

        Yes, I clarified that in my previous post, sorry for the confusion. 

> )       Well I'll take that as a compliment, since I am DALnet's hostmaster. :)
> ) However I regret to inform you that I did use the CNAME hack to fine
> ) tune our load balancing.
> Ah, so that explains why nslookup barfs when I try to lookup irc.dal.net
> repeatedly.

        A) Define "barfs." B) nslookup has peculiarities of its own, dig is a
much better tool. C) I never have any problems with it so I'd be curious
to know what you mean. :)

> )                          I'd also like to point out that the IP's in a
> ) true round-robin setup (as manifest with BIND, et al) will be returned
> ) randomly, not in a rotate once cycle.
> Well, if that is true, then it's because of your setup. BIND will rotate
> IPs once per query, and that's documented behaviour.

        Chapter and verse?  Rotate yes, rotate left one cycle (I'm 98% sure)
no. 

> For an easier to see example, nslookup nanog.random.ml.org a couple times.

        I strongly suspect that the behavior you're seeing is due to the small
sample set. Try it with 10 IP's or more. Also, I was speaking
specifically about how the server answers queries. You have a TTL of 8
hours, after the first answer you're getting resolver cache. 

> )       Finally, if you plan to disagree with anything in this post, please
> ) quote chapter and verse from the relevant RFC. I've spent a lot of time
> ) studying this topic and am quite sure of my facts.
> I'd rather come up with evidence as opposed to rhetoric, but if you
> insist...
>
> Well, I downloaded bind-8.1.2-doc.tar.gz, but I don't really have the time
> currently to look through it to find out specific examples in the
> documentation.

        I'll be here. :)

Doug
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