nslookup issues on hp-ux
Kevin Darcy
kcd at daimlerchrysler.com
Mon Feb 26 22:27:42 UTC 2001
Praveen Kumar Amritaluru wrote:
> >
> > Praveen Kumar Amritaluru wrote:
> >
> > > >
> > > > At 06:33 22.02.2001 -0800, you wrote:
> > > >
> > > >
> > > > >Okay, now I'm really confused. I thought nslookup called resolver
> > > > >routines, which are supposed to check /etc/nsswitch.conf. The libbind.a
> > > > >looks like it compiles its own versions of the resolver routines, then
> > > > >gets linked into nslookup. So it is not using the native resolver routines
> > > > >from HP-UX, which, according to the man pages, go to nsswitch.conf to see
> > > > >where to resolve from. Also, both texts I consulted ("DNS and BIND, 3rd
> > > > >Ed." and "(The Concise Guide to) DNS and BIND") describe this resolver
> > > > >behavior, that nslookup uses the resolver to find which service to use
> > > > >(files, DNS or NIS). I'm very confused at this point and don't know what
> > > > >to believe...
> > >
> > > Still nslookup that comes up with HP's distribution will be
> > > following /etc/nsswitch.conf file. If you want the latest version
> > > of nslookup, then try downloading BIND 8.1.2 on HP-UX available
> > > at http://www.software.hp.com.
> > >
> > > But the public domain nslookup code does not use the
> > > /etc/nsswitch.conf file and more over the nslookup is built from
> > > static library libbind.a which does not read the nsswitch.conf
> > > file. nslookup that you were using earlier should be working
> > > well with new version of BIND.
> > >
> > > Public domain nslookup code should be doing this modification,
> > > as IP add. - hostname information is stored not just in DNS,
> > > but also in FILES & NIS.
> >
> > I disagree vehemently. nslookup is a *DNS-specific* lookup tool. It comes with the
> > BIND distribution; in fact, its code was ripped out of an early BIND codebase and
> > made standalone. The "ns" in "nslookup" is echoed from "DNS". Nobody ever intended
> > it to be the all-singing, all-dancing, generic lookup tool for all naming sources
> > in the known universe, and in fact it would be horrible for that, since it only
> > understands a DNS or DNS-like naming hierarchy. It would be totally hopeless, for
> > instance, trying to navigate X.500, Active Directory or even NetInfo.
> >
> > Besides, the more useful you make nslookup, the longer it lives. It should have
> > already been buried by now, because of all of its quirks and flaws.
> >
> >
> > - Kevin
> >
>
> I dont want to get into discussion on whether nslookup should be
> obsoleted or not as there was already a big discussion on this
> mailing-list over this issue.
>
> It may be true that there are flaws in nslookup.
>
> But the fact is that there are lot of people who still use
> nslookup and would not be able to migrate from nslookup to other
> tools within a short period of time.
>
> It is for these people that the value add of nslookup will be
> very useful.
>
> It may be true that nslookup was a tool that got developed from
> BIND code base and was not intended to be all singing.... But
> it is also true that people will still need a tool to query for
> hostname resolution irrespective of whether they are using
> DNS/FILES/NIS etc...
>
> If nslookup is not going to be the tool that is going to do the
> resolution of hostnames to IP address and viceversa, then there
> should be some other tool that will do this for the users in
> place of nslookup. I dont see any reasons why a single tool
> should not be used and avoid usage of different tools for
> querying different sources in place of a single tool.
>
> If nslookup can be modified without much complexity to query
> other databases then the same can be used.
There is no one standard for how to name things, or even how to name computers. Each
naming service is free to use its own structure and semantics. For this reason, I think
the expectation that there can somehow be a tool which is able to query *all* possible
naming sources is rather impractical.
Just use the tools which are appropriate for the particular naming service. nslookup is
appropriate (if at all) exclusively for DNS. "grep" or other text-fie-oriented
utilities are appropriate for retrieving data from the /etc/hosts text file. Use
whatever lookup tool is appropriate for Yellow Plague (aka NIS or NIS+).
- Kevin
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