asked on 2012 R2 DC not reachable
Hi,
my business and I service about 300 customers in the small business range, mostly with pure Microsoft environments.
Our so far only two customers who run no servers other than Windows Server 2012 R2 experience this problem:
Every now and then, every other day or less frequent, logon into RDS is not possible because no domain controller is available. DNS service does not work even though the service is running. The AD member servers log frequent events relating to no DC available. The DC logs no events, feels just fine, cannot resolve any DNS queries and sits there in ignorant bliss.
Restart of the service does not help, I have to reboot the entire machine .
Both customers run VMware, one has Exchange, the other does not. Both customers have only one single DC. One domain, one tree.
Eventlog does not record anything of any help.
Many other customers run Server 2012 R2 for some services and 2008 R2 for others. They don't report anything like this.
Does anybody have a clue what might be happening there? Has anyone experienced something like that?
Thanks,
Ralph
my business and I service about 300 customers in the small business range, mostly with pure Microsoft environments.
Our so far only two customers who run no servers other than Windows Server 2012 R2 experience this problem:
Every now and then, every other day or less frequent, logon into RDS is not possible because no domain controller is available. DNS service does not work even though the service is running. The AD member servers log frequent events relating to no DC available. The DC logs no events, feels just fine, cannot resolve any DNS queries and sits there in ignorant bliss.
Restart of the service does not help, I have to reboot the entire machine .
Both customers run VMware, one has Exchange, the other does not. Both customers have only one single DC. One domain, one tree.
Eventlog does not record anything of any help.
Many other customers run Server 2012 R2 for some services and 2008 R2 for others. They don't report anything like this.
Does anybody have a clue what might be happening there? Has anyone experienced something like that?
Thanks,
Ralph
Windows Server 2012Active Directory
Last Comment
Ralph Scharping
ASKER
Thas is the case. Memory is not oversubcribed.
You can try forcing DNS to listen on IP: http://www.tomshardware.co.uk/faq/id-1943765/windows-server-2012-dns-server-accessible-unable-resolve-dns-queries.html
ASKER
DNS is already configured as described.
And OS is updated?
ASKER
Yes, no patches available.
Another thing, your DNS is configured to use any kind of router as forwarder?
ASKER
No, I am forwarding to google. But resolving even internally does not work when the issue occurs.
You can try disabling EDNS0, on command prompt run dnscmd /config /EnableEDNSProbes 0
Not requires restarts.
Not requires restarts.
ASKER
The command went through without an error message. But I'll have to wait a few days to check if this changed anything.
Somehow I don't think it is an isolated DNS issue...
Somehow I don't think it is an isolated DNS issue...
Which type of NIC are the VMs using? They should be using Vmxnet3.
ASKER
They are not. Default is E1000 on VMware 5.5 and that's what they are.
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ASKER
Thank you for this hint. I will change that and retry. But I will need to wait a week to verify if this is really better.
ASKER
I'm thinking we might be on the right track here. Just exchanged the LAN adapters on all VMs. First thing I notice is MUCH faster logon times...
:-)
ASKER
So far so good. No crashes yet since I made the change.
ASKER
Perfect!
I just wonder why the creation of a new VM defaults to E1000.
No trouble since I changed it....
Thanks a million!
I just wonder why the creation of a new VM defaults to E1000.
No trouble since I changed it....
Thanks a million!
Ensure vmware don´t do oversubscription/overcommi