NetBackup has been doing hostname lookup caching for quite sometime for now. 
But it was only in-memory and, so, restricted to the process. That also meant, 
restarting NB services helped to clear the cache.

However, in-memory hostname lookup caching does not help many of the processes 
who may be looking up the same name/IP that some other process already did. 
Knowing DNS performance to be an issue in many environments, NetBackup 
minimized its load on DNS by creating persistent hostname lookup cache.

NetBackup has per-host bp.conf setting VNET_OPTIONS that controls some aspect 
of this cache. Running "bptestnetconn -bv" (6.5.6, 7.0.1+, not 7.0) displays 
these settings.

NetBackup 7.1 introduced another field in VNET_OPTIONS to disable persistent 
hostname lookup cache - for those rare cases that may need it. Note that 
disabling persistent hostname lookup cache makes NetBackup perform more DNS 
queries - impacting NetBackup performance. What is the exact impact depends on 
the environment/setup.

Steps:
- To disable persistent hostname lookup cache, first check if you are using 
VNET_OPTIONS (bp.conf/registry). Run "bptestnetconn -b" and look for 
VNET_OPTIONS lines in the output.

- If you are already using VNET_OPTIONS, just change/add 11th field set to '1'.

- If you are not using VNET_OPTIONS, run "bptestnetconn -b" to make sure that 
no VNET_OPTIONS field appear. Now, add
  VNET_OPTIONS = 120 0 200 40 0 0 0 5 0x701 0 1 0
- Confirm that only the following "new" VNET_OPTIONS field appears in 
"bptestnetconn -b" output:
  VNET_OPTIONS (disable file cache)        = 1         [0]

HTH,
/Girish


--- On Thu, 6/2/11, Lightner, Jeff <jlight...@water.com> wrote:

> From: Lightner, Jeff <jlight...@water.com>
> Subject: Re: [Veritas-bu] Where is my IP hiding?
> To: "James Pattinson" <ja...@pattinson.org>
> Cc: "Martin, Jonathan" <jmart...@intersil.com>, 
> VERITAS-BU@MAILMAN.ENG.AUBURN.EDU
> Date: Thursday, June 2, 2011, 7:43 PM
> Yep - there was a fairly long thread
> here before where someone else
> complained about applications that do their own name
> caching saying it
> wasn't their job.
> 
> By the way this started in 7.01 not 7.1 as I said
> before.   The technote
> that tells how to manually delete the cache directory files
> is:
> http://www.symantec.com/business/support/index?page=content&id=TECH14111
> 7&key=15143&actp=LIST
> 
> -----Original Message-----
> From: James Pattinson [mailto:ja...@pattinson.org]
> 
> Sent: Thursday, June 02, 2011 10:02 AM
> To: Lightner, Jeff
> Cc: Martin, Jonathan; VERITAS-BU@MAILMAN.ENG.AUBURN.EDU
> Subject: Re: [Veritas-bu] Where is my IP hiding?
> 
> Jeff,
> 
> Arggh, that was it. I thought rebooting cleared the host
> cache since I 
> remember reading that restarting NBU processes had the same
> effect. I 
> guess not.
> 
> That's at least the third time this has bitten me, am
> starting to 
> dislike this new feature somewhat. I even mentioned it in
> my original
> email!
> 
> Cheers
> James
> 
> On 02/06/2011 14:58, Lightner, Jeff wrote:
> > With 7.1 NBU is now doing its own caching of
> names/ips.
> >
> > Relevant commands:
> > bpclntcmd -hn<hostname>  = Shows what IP it
> thinks the host has
> > bpclntcmd -ip<IP Address>  = Shows what
> name it thinks is associated
> > with the host.
> > bpclntcmd -self = Shows what hostname/IP it thinks the
> host you are on
> > has.
> > bpclntcmd -clear_host_cache = Clears the cache.
> >
> > There is a technote about this that also tells you how
> to delete the
> > cache files completely if the above command doesn't
> help.   I find
> > clearing the cache with the command seems to work
> well.
> >
> > -----Original Message-----
> > From: veritas-bu-boun...@mailman.eng.auburn.edu
> > [mailto:veritas-bu-boun...@mailman.eng.auburn.edu]
> On Behalf Of
> Martin,
> > Jonathan
> > Sent: Thursday, June 02, 2011 9:52 AM
> > To: James Pattinson; VERITAS-BU@MAILMAN.ENG.AUBURN.EDU
> > Subject: Re: [Veritas-bu] Where is my IP hiding?
> >
> > Shot in the dark here. Have you checked WINS? We have
> a *very*
> annoying
> > issue here where old WINS records take precedence over
> DNS via the
> "WINS
> > lookup" functionality in DNS. We normally have to
> tombstone the record
> > in WINS and clear the DNS cache to resolve.
> >
> > -Jonathan
> >
> > -----Original Message-----
> > From: veritas-bu-boun...@mailman.eng.auburn.edu
> > [mailto:veritas-bu-boun...@mailman.eng.auburn.edu]
> On Behalf Of James
> > Pattinson
> > Sent: Thursday, June 02, 2011 9:49 AM
> > To: VERITAS-BU@MAILMAN.ENG.AUBURN.EDU
> > Subject: [Veritas-bu] Where is my IP hiding?
> >
> > Hi All
> >
> > Am running a NetBackup 7.1 testbed on Windows. VMware
> has decided it's
> > time to change my IP address so I have updated the
> hosts file on the
> > master server.
> >
> > NetBackup now absolutely refuses to work after several
> reboots. I can
> > ping my master server by name, and forward and reverse
> lookups go to
> the
> >
> > correct IP address.
> >
> > It seems that problem is that any EMM type commands
> still have the old
> > IP somewhere, and I'm getting status 334 (EMM
> Initialization Failed)
> > when I run pretty much anything.
> >
> > When I run netstat -a I see several SYN_SENT
> connections to the old IP
> > (pbx port) that is no longer relevant.
> >
> > I've had a quick look through the NBU parts of the
> Registry but can't
> > find anything.
> >
> > Where is this IP coming from? I'm pretty sure it's not
> the highly
> > annoying new netbackup IP cache as I have rebooted
> several times.
> >
> > Cheers
> > James
> >
> >
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