SUMMARY: SunOs 4.1.4 and resolv+

From: Martin Achilli (
Date: Mon Feb 05 1996 - 09:43:00 CST

This is my summary on the problems I have had trying to use the
modified resolver libraries - resolv+ 2.1.1 - with SunOs 4.1.4. I
received 3 responses, this morning I tried one last time and understood
the problem. The main complaint from my users was that they could not
use netscape.

The resolv+ libraries allow you to perform hostname > address lookups
by consulting the hosts file, then NIS and then a nameserver. You can
also configure NIS to consult a nameserver by adding the B=-b option in
/var/yp/Makefile. The reason things would not work is that I had
changed my NIS slave server. Whereas the old slave server could contact
a nameserver, the new one couldn't.

This is where I got caught. Many of the system utilities like ping, ftp
will use the resolv+ libraries and do lookups in the order
hosts,nis,dns BUT there are two netscape binaries one for hosts,nis
lookups and one for dns lookups.

So if you have resolv+ installed and don't have the B=-b option what
happens is that ping and ftp work but netscape (non-dns version) won't.
Lookups are performed by querying hosts then nis then dns as resolv+
was made to do. If you have resolv+ installed and have the B=-b option
what happens is that resolv+ is not really being used. Lookups are
performed by querying hosts then nis AND after this it is the ypserv
daemon that you are bound to that performs the lookup. If the host this
deamon is running on can't contact a nameserver then things won't

I was being confused by the fact that sometimes a host would be bound
to ypserv on the master server (which can contact a nameserver) and
sometimes to the slave server (which couldn't). Also the fact that ping
and netscape work in a different manner made things worse.

I also installed the international libc patch 102545-02, I have
discovered there is version -04 out now, but anyway it did not make ANY

Thanks to Heas H. Heas and to Chris Eastman who were very helpful, I
also read a summary dated 27th Oct '94 by Joe Merola but it did not
help. If someone could explain to me the interaction between the "B=-b"
option of /var/yp/Makefile and resolv+ in more detail I would be


Martin Achilli -
Consiglio Nazionale delle Ricerche - I.N.B.
c/o Medicina Nucleare, Osp. San Raffaele
20132 Milano, Italy
tel: +39/2/26433648 fax: ../26415202

Original question:
> I recently upgraded our 4/470 from 4.1.3 to 4.1.4 and am now
> having strange problems with name resolution via NIS/DNS.
> In the 4.1.3 installation I was using the resolv+2.1.1 library to perform
> name resolution first via the hosts file then via NIS and at last with
> DNS.
> Since I installed 4.1.4 I am having intermittent problems, the
> 4.1.4 installation includes the international libc patch 102545-02 and
> 102264-02 102394-01 102422-01 102516-02 102612-01 102618-01 103058-01.
> The problem seems to be that any name resolution operation first tries
> the hosts file then NIS and it tries and tries with NIS for a long time
> before using DNS, in fact if I kill the ypbind daemon or remove NIS
> from the search order path name resolution is performed via DNS after a
> second or two. I have put the B= -b flag in /var/yp/Makefile and I
> think everything is set up as it used to be when I had 4.1.3, but there
> still are some problems.
> Does someone know why things won't work now ? Are there pitfalls when
> using resolv+2.1.1 with 4.1.4 ? I have read through the old summaries
> and the FAQ but unfortunately I am still lost..

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