resolver values

[Kevin Darcy]

I'm not sure whether MAXNS applies to resolvers or not; it might only be
used in named itself. Remember that BIND, the package, comprises a
nameserver, a resolver library, and a bunch of other utilities. Some of
these #include-file parameters may only apply to one part or another,
but not all of them.

Can you recompile with a bigger limit? Probably. But then in order for
this to be effective, you'd have to replace your system resolver with
the recompiled one. Do you really want to do that? You could pretty much
kiss vendor support goodbye if you do such a thing, since neither Sun
nor HP will probably support any resolver issue you have, when their
libraries have been replaced with recompiled ones.

Before taking such a radical step, I'd verify whether the currently
compiled-in limit (which may have been altered by your vendor, relative
to the BIND-distribution default) is sufficient for your needs. Put a
bunch of bogus nameservers in resolv.conf, followed by a good one, and
see if your application(s) can still resolve names. The proof is in the
pudding.


- Kevin

"Georgeson, Evan [NCSUS Non J&J]" wrote:

>
>
> Thanks Kevin, I just was reading on old 2nd ed Evi Nemeth book and it
> mentioned you could have up to 3. As for the search directive my
> further reading reveals a maximum of 6 domains can be listed...I sort
> of answered my own question but here's a last one. How deep can each
> search domain descend, e.g., 111.222.333 111.222.333.444, does BIND
> care? And, can these values be altered at compile time? Here's what
> resolv.h has to say. Btw, I'm new to DNS and I didn't compile this
> BIND on our machine, these values seem to me that they can be adjusted
> prior to compiling...Thanks again for your input
>
> #define MAXNS                   3       /* max # name servers we'll
> track */
> #define MAXDFLSRCH              3       /* # default domain levels to
> try */
> #define MAXDNSRCH               6       /* max # domains in search
> path */
> #define LOCALDOMAINPARTS        2       /* min levels in name that is
> "local" */
>
> #define RES_TIMEOUT             5       /* min. seconds between
> retries */
> #define MAXRESOLVSORT           10      /* number of net to sort on */
>
> #define RES_MAXNDOTS            15      /* should reflect bit field
> size */
> #define RES_MAXRETRANS          30      /* only for
> resolv.conf/RES_OPTIONS */
> #define RES_MAXRETRY            5       /* only for
> resolv.conf/RES_OPTIONS */
> #define RES_DFLRETRY            2       /* Default #/tries. */
> #define RES_MAXTIME             65535   /* Infinity, in milliseconds.
> */
>
> -----Original Message-----
> From: Kevin Darcy [mailto:kcd at daimlerchrysler.com]
> Sent: Tuesday, April 30, 2002 9:11 PM
> To: BIND Users (E-mail)
> Subject: Re: resolver values
>
>
> "Georgeson, Evan [NCSUS Non J&J]" wrote:
>
> > If someone could point me to an answer to this long query I'd be
> very
> > grateful...
> >
> > I'm looking for the rules and max. values that are contained in the
> > resolv.conf file on both a Solaris 2.6 (BIND 8.2.5)and HPUX 10.20
> (BIND
> > 4.9.7)system. More specifically, I'm pretty sure you can only have
> up to 3
> > nameserver entries but I don't seem to have a firm value for the
> number of
> > entries you can have in the search line. The resolver man pages
> weren't
> > helpful. Thanks in advance.
>
> I think you can have as many nameservers as you want, but it doesn't
> really
> matter since the resolver will time out before it gets very far. We
> use 3,
> and even then, sometimes the resolver times out before it gets to the
> third
> one.
>
> - Kevin
>