Losing Host name and Display name in DCR

Answered Question
Mar 16th, 2010
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Since upgrading to LMS3.2 there are approximately 20 devices that are losing the entered host and display names each day. I have reset these, but they are cleared during one of the processes running overnight. How can I resolve this issue?

Correct Answer by Joe Clarke about 7 years 1 week ago

Yes, this could explain it.  I have been trying to reproduce, and I cannot.  One thing to try would be to add some static entries for the problem devices to the server's local hosts file.  Then, use NMSROOT/bin/resolver.pl to test that IP-to-name resolution is working:


NMSROOT/bin/perl NMSROOT/bin/resolver.pl IP


If that works, run a new Discovery, and see if the same problem occurs.

Correct Answer by briancwhiting about 7 years 1 week ago

We had a similar problem here.  What it turned out to be for us was a mismatch between DNS, Reverse DNS, and the hosts file on the LMS server.  Once they were synchronized properly the name loss stopped.  We are beginners with LMS though.

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Joe Clarke Tue, 03/16/2010 - 19:28
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Cleared how?  To what value is the display name being set?  Is it being set to the IP?  Can you correlate Discovery times to these changes?

marshajr Tue, 03/16/2010 - 20:14
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Joe - the Host and Display name are being set to the IP Address.


The Discovery process ran at 18:00 last night (16th). The Change Audit Report indicates that the 20 affected devices were modified by 'admin' at 18:20.


It is always the same subset of devices that is affected by this.

Joe Clarke Tue, 03/16/2010 - 21:15
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To confirm the problem is really discovery, can you correct the devices, then run a manual discovery job, and see if the hostname and display name change?

marshajr Tue, 03/16/2010 - 22:08
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Joe - I just ran the discovery job, and 22 devices have now reverted to showing IP for Host and Display name.


Regards ... Jon

Leo Laohoo Tue, 03/16/2010 - 21:27
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Same here Joe.  After a few days a number of my devices (>100 or so) the hostname and display name would be replaced by the IP addresses.  I have tried to export and correct the entries but the problem just comes back.

Martin Ermel Wed, 03/17/2010 - 10:45
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what are your Discovery Settings for the "Global Settings" section ?


marshajr Thu, 03/18/2010 - 17:03
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My Global Discovery settings are almost the same, except we are using LoopBack for the preferred Management IP.

Correct Answer
briancwhiting Fri, 03/19/2010 - 06:34
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We had a similar problem here.  What it turned out to be for us was a mismatch between DNS, Reverse DNS, and the hosts file on the LMS server.  Once they were synchronized properly the name loss stopped.  We are beginners with LMS though.

Correct Answer
Joe Clarke Fri, 03/19/2010 - 11:53
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Yes, this could explain it.  I have been trying to reproduce, and I cannot.  One thing to try would be to add some static entries for the problem devices to the server's local hosts file.  Then, use NMSROOT/bin/resolver.pl to test that IP-to-name resolution is working:


NMSROOT/bin/perl NMSROOT/bin/resolver.pl IP


If that works, run a new Discovery, and see if the same problem occurs.

marshajr Sun, 03/21/2010 - 18:24
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Thanks Brian and Joe - this appears to have fixed the problem - I do recall having a similar problem several versions ago with dfm and using the host file to fix it.

swapanshah Mon, 06/21/2010 - 07:00
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Hi,


We are having the same problem at the moment, how did you end up resolving the issue?

Brian Whiting Wed, 12/15/2010 - 08:02
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The issue was a result of the discovery settings.  There is a setting called "Update DCR Display Name" in the DCR Administration settings portion of configure discovery.  If the box is checked the discovery process will overwrite the friendly name with whatever the DNS or reverse DNS name resolution comes up with.  We unchecked the box and the problem has gone away.

Michel Hegeraat Wed, 12/15/2010 - 08:35
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I think DFM will still do a hostname lookup despite the set displayname in the DCR. So you will get ip addresses in DFM alarms and events.


Better convert your device list to a local hostfile


Cheers,


Michel

Joe Clarke Sat, 12/18/2010 - 08:22
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Michel is correct.  DFM does not respect the DCR display name.  You must make sure that your management IP address is properly resolvable in DNS or the server's local hosts file.  Use the NMSROOT/bin/resolver.pl script to confirm that this resolution is properly setup.  For example:


NMSROOT/bin/perl NMSROOT/bin/resolver.pl 10.1.1.1


Make sure you get back a hostname.

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