Name Resolution

[Jack F. Vogel]

In article <9105142216.AA18344 at ucbvax.Berkeley.EDU> freese at dalvm41b.vnet.ibm.com ("Bradley T. Freese") writes:
>RRH at vm.nrc.ca writes:
|
|> Hello Netters,
|> Our AIX user has run into another question/problem. On our SUNs &
|> SGIs  the command ping vm works. The host vm has a fully qualified name
|> of  vm.nrc.ca . The AIX, SUN and SGI are in the di.nrc.ca domain.
|> However  the ping vm fails and ping vm. or ping vm.nrc.ca   The
|> /etc/resolv.conf has domain di.nrc.ca.  Is there any way to tell   the
|> AIX machine  to behave like the others or are we stuck with it?
 
|In a word, yes.  The behavior you report is standard for AIX.

Standard on the 6000 maybe which still has an older level of BIND. On
AIX 1.2.x which has BIND 4.8.1 what he is asking for will work. If I
say 'ping host' the resolver (the application interface half of BIND)
will first formulate a query of 'host.la.locus.com', if this is resolved
it stops, however if it fails it will next try 'host.locus.com'.

|Basically, AIX has two methods for resolving a name, based on whether
|it has a period ('.') in it.  If the name has a period *anywhere* in
|it, AIX simply passes it to the domain name servers unchanged.  If
|the name has no period in it, AIX appends the domain name found
|in /etc/resolv.conf and passes the result to the name servers.  Either
|way, if the name servers do not respond, AIX searches through
|/etc/hosts and then quits.

Your terminology is a bit confused here. You speak of two entities
'AIX' and the 'nameserver'. This is not correct, the exchange takes
place between the two halves of the BIND package: the resolver and
the nameserver. The resolver will necessarily run on the AIX system,
the nameserver may or may not, depending. The resolver is a set of
routines in libc.a that an application makes use of. When you use
'ping' it calls gethostbyname() and that routine in turn makes
use of the resolver routines. The problem as I said, is that the
resolver/nameserver code on the 6000 is very old, I don't even know
what BSD sid level it is. More recent BSD code behaves in the way
this user is describing, and as he notes SUN and SGI have provided
the more recent code, as we did in the AIX 1.2.x product on the PS/2
and 370.

I have said this before and I will say it again, for customers on the
Internet BIND is critical! It is what makes an internet with thousands
of hosts possible. It is important, in my estimation, to provide customers
with the current level of functionality in this code. So, the 6000
support folk should, in my opinion, seriously consider upgrading their 
code as well. Furthermore, the code is reasonably portable, it should
be a painless task, and think how many happy faces you'll get :-}.

Disclaimer: I don't speak for LCC, and certainly not for IBM.

-- 
Jack F. Vogel			jackv at locus.com
AIX370 Technical Support	       - or -
Locus Computing Corp.		jackv at turnkey.TCC.COM