[HPADM] RE: Summary: NIS Question

• Previous message: Johnson, Craig E: "[HPADM] NIS Question"
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To: "'hpux-admin@DutchWorks.nl'" <hpux-admin@DutchWorks.nl>
Date: Wed, 30 Jul 2003 08:45:36 -0700

Thanks to all who responded: Jon Bidinger, Nahkola Mikko, Jothish.
 
I absolutely have the "B=-b" set in the Makefile and never even knew it! :)
Thanks again!
 
Craig

attached mail follows:

To: "Johnson, Craig E" <Craig.E.Johnson@icn.siemens.com>
Date: Tue, 29 Jul 2003 23:39:07 -0700

On Tue, Jul 29, 2003 at 03:36:40PM -0700, ext Johnson, Craig E wrote:

> I am seeing something very strange. There were a few clients, both Sun
and
> HP, that were lacking a /etc/resolv.conf file and an /etc/nsswitch.conf
> file, so DNS wasn't working locally. Both were bound to NIS servers that
> DID have both of those files, which in turn had "dns" specified in the
first
> entry of the hosts line in nsswitch.conf. Here's the thing:
>
> # ypmatch hpserv24 hosts
> 139.21.xxx.xxx hpserv24.mch4.....
> # ypcat -k hosts | grep -i hpserv24
> #
>
> So, it gets resolved even though it isn't present in my local NIS maps.
How
> is this possible? Is the NIS slave/server actually using DNS, as
specified
> in the nsswitch.conf file, to resolve it and return the IP to the NIS-only
> client?

I'm not sure but I've read about something that would sound familiar ...
now where's my copy of "Installing and Administering NFS Services" ...
(the edition covering 10.20 ACE/HWE seems to be B1031-90043, I should
have a newer copy around somewhere, and it should be on docs.hp.com and
the CDs too.)

There is indeed a feature that is sometimes called "server-side hostname
fallback" that, when turned on, should make your NIS server do the DNS
query in question and return that through NIS.

This is "not recommended if you have a choice" and seems to be turned off
by default on HP-UX, but can be enabled easily by editing
/var/yp/Makefile. The critical part would be the -b switch to makedbm
(see the man page).

Now, I have never tried to turn that on myself, but I'd expect that the
results would be somewhat like you describe.

-- 
Mikko Nahkola   <mikko.nahkola@nokia.com>
Tre-IN sysadmin <mnahkola@trein.ntc.nokia.com>

attached mail follows:

To: "Johnson, Craig E" <Craig.E.Johnson@icn.siemens.com>
Date: Tue, 29 Jul 2003 20:25:13 -0700

Depending on how your NIS is setup it can be configured to refer to
DNS if the host queried isn't in it's maps.

On a Sun system it's at about line 20 of the /var/yp/Makefile

# Set the following variable to "-b" to have NIS servers use the
domain name
# resolver for hosts not in the current domain.
#B=-b
B=

On Tue, Jul 29, 2003 at 03:36:40PM -0700, Johnson, Craig E wrote:
> I am seeing something very strange. There were a few clients, both Sun
and
> HP, that were lacking a /etc/resolv.conf file and an /etc/nsswitch.conf
> file, so DNS wasn't working locally. Both were bound to NIS servers that
> DID have both of those files, which in turn had "dns" specified in the
first
> entry of the hosts line in nsswitch.conf. Here's the thing:
>
> # ypmatch hpserv24 hosts
> 139.21.xxx.xxx hpserv24.mch4.....
> # ypcat -k hosts | grep -i hpserv24
> #
>
> So, it gets resolved even though it isn't present in my local NIS maps.
How
> is this possible? Is the NIS slave/server actually using DNS, as
specified
> in the nsswitch.conf file, to resolve it and return the IP to the NIS-only
> client?
>
> Thanks for anything!
>
> Craig
>
>
> Craig Johnson
> Systems Administrator/Sr. Engineer
> Siemens
>
>

-- 
Jon Bidinger     | "How many legs does a dog have if you call the tail a
leg?
jon@bidinger.org | Four. Calling a tail a leg doesn't make it a leg."	
                 |                                      --Abraham Lincoln

attached mail follows:

To: "Johnson, Craig E" <Craig.E.Johnson@icn.siemens.com>
Date: Wed, 30 Jul 2003 02:59:03 -0700

Nis server can resolve from DNS if B=-b option is set in /var/yp/Makefile ..
 
 
Jothish

-----Original Message-----
From: Johnson, Craig E [mailto:Craig.E.Johnson@icn.siemens.com]
Sent: Wednesday, July 30, 2003 4:07 AM
To: 'hpux-admin@DutchWorks.nl'
Subject: [HPADM] NIS Question

I am seeing something very strange. There were a few clients, both Sun and
HP, that were lacking a /etc/resolv.conf file and an /etc/nsswitch.conf
file, so DNS wasn't working locally. Both were bound to NIS servers that
DID have both of those files, which in turn had "dns" specified in the first
entry of the hosts line in nsswitch.conf. Here's the thing:
 
# ypmatch hpserv24 hosts
139.21.xxx.xxx hpserv24.mch4.....
# ypcat -k hosts | grep -i hpserv24
#
 
So, it gets resolved even though it isn't present in my local NIS maps. How
is this possible? Is the NIS slave/server actually using DNS, as specified
in the nsswitch.conf file, to resolve it and return the IP to the NIS-only
client?
 
Thanks for anything!
 
Craig
 

Craig Johnson
Systems Administrator/Sr. Engineer
Siemens

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