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Thierry101
2 Iron

Backup NLB Servers - name server may be misconfigured

Hello all

windows 2008r2, Networker 7.6.3.7

NLB servers are as below

ping APPV01

Pinging APPV01.abc.com [x.x.x.42] with 32 bytes of data:

Reply from x.x.x.42: bytes=32 time=1ms TTL=128

ping -a x.x.x.43

Pinging APPV01 [x.x.x.43] with 32 bytes of data:

Reply from x.x.x.43: bytes=32 time=9ms TTL=128

ping APPV02

Pinging APPV02.abc.com [x.x.x.44] with 32 bytes of data:

Reply from x.x.x.44: bytes=32 time=1ms TTL=128

ping -a x.x.x.45

Pinging APPV02 [x.x.x.45] with 32 bytes of data:

Reply from x.x.x.45: bytes=32 time=17ms TTL=128

The servers were rebooted and now throwing these error in backup. Was working fine before

39077:save: error, Warning, cannot resolve host 'APPV02.abc.com' to 'x.x.x.42', name server may be misconfigured.

39077:save: error, Warning, cannot resolve host 'APPV01.abc.com' to 'x.x.x.44', name server may be misconfigured.


Backup (Global 1of 2)

appv01

appv01.abc.com

x.x.x.43 (tried with 42 too but same)

appv02

appv02.abc.com

x.x.x.45 (tried with 44 too but same)

Any best practice in backing up NLB servers would be appreciated..thank you

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9 Replies
ble1
5 Iridium

Re: Backup NLB Servers - name server may be misconfigured

Set in in DNS/hosts table.

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Thierry101
2 Iron

Re: Backup NLB Servers - name server may be misconfigured

Thanks for the reply Hrvoje

But it was working fine before...what could possibly broke it?

thanks again

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ble1
5 Iridium

Re: Backup NLB Servers - name server may be misconfigured

Well, something happened for sure. In the past I have seen similar issue with multihomed machines (where they had several interfaces within same subnet) and reboot after patching would bring similar situation (it was not patches, but rather order of nics which changed within Windows).  It doesn't matter if this is a match to your case or not - point is that something has changed and best way to address it is to address error itself.  Your issue seems to indicate that gethostbyip() and gehostbyname() have issues - perhaps DNS is not in place or it started to forward request to second DNS which has different answer - who knows.  To get the bottom you need to test is.

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Thierry101
2 Iron

Re: Backup NLB Servers - name server may be misconfigured

Hi Hrvoje

What to test and expected output is the query 🙂

Have checked the NLB, Teaming, DNS orders, etc, nslookup

We have another twin APPV servers which wasnt rebooted but working ok so far...have cross check the configs as well..nothing amiss

not finding anything that breaking it....

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ble1
5 Iridium

Re: Backup NLB Servers - name server may be misconfigured

> What to test and expected output is the query 🙂

The error you reported is:

39077:save: error, Warning, cannot resolve host 'APPV02.abc.com' to 'x.x.x.42', name server may be misconfigured.

39077:save: error, Warning, cannot resolve host 'APPV01.abc.com' to 'x.x.x.44', name server may be misconfigured.


Now, you already have hint above - it is reported by save so it is the client that at the time of run could not resolve these servers to IPs given.  And the error says that during gethostbyip() return for APPV02.abc.com was not x.x.x.42 (nor was x.x.x.44 for APPV01.abc.com).

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Thierry101
2 Iron

Re: Backup NLB Servers - name server may be misconfigured

Hi Hrovje

These were checked:-

-nslookup

-ping

-ping -a

-NLB

-Teaming

-DNS

all returns FQDN and x.x.x.42 which looks ok and non-suspicious but Networker still doesnt like it

Globals 1 of 2 have these entries, setup by vendor (to ensure NLB works-it has been working before)

appv01 (resolves to x.x.x.42)

appv01.abc.com (resolves to x.x.x.42)

x.x.x.43 [resolves to APPV01 but not registered in DNS]-NLB virtual name]

I am trying to understand causes on Networker refusing to backup now since there was no changes at all on backup configs.

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ble1
5 Iridium

Re: Backup NLB Servers - name server may be misconfigured

Because what you have may be spoofing.  You said yourself, appv01 is 43.  Now you say that .43 claims the same. Each IP should have different name associated with.

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Thierry101
2 Iron

Re: Backup NLB Servers - name server may be misconfigured

yep

I have no idea how NLB works and its a pain...


C:\Windows\system32>nslookup xx.xx.xx.42

Server:  dc-01.xx.xx.xx.xx

Address:  xx.xx.xx.10

Name:    appv01.xx.xx.xx.xx

Address:  x.x.x.42

C:\Windows\system32>nslookup x.x.x.43

Server:  dc-01.xx.xx.xx.xx

Address:  x.x.x.10

*** dc-01.xx.xx.xx.xx can't find 10.32.64.43: Non-existent domain

C:\Windows\system32>ping -a xx.xx.xx.43

Pinging APPV01 [xx.xx.xx.43] with 32 bytes of data:

Reply from xx.xx.xx.43: bytes=32 time=17ms TTL=128

C:\Windows\system32>

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ble1
5 Iridium

Re: Backup NLB Servers - name server may be misconfigured

It is possible that it uses NB name - check what will ipconfig /all give you.

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