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DNS issue on DC with multiple NICS

prutter asked
Last Modified: 2013-12-05
I have a ohysical server (DC) in a VMware environment that has multiple nics and i have a DNS issue.  This server is a DC that i am only useing as a backup DC and a VCB server for VMware.  One nic goes to the LAN and the other nic goes to the iSCSI network for the VCB backups.  I don't have any DNS settings on the iSCSI nic and i do with the LAN nic.  My file replication runs into problems replicating due to a lookup issue.  When i try to ping server.company.com i get a timeout.  When i trqacert the same name it reponds with the IP address of the iSCSI nic.  i've since changed it in my internal DNS to reflect the LAN address of server.company.com and this mornign things were changed back.  I flushed DNS after the changes (last week) and re-registered.  I came in this morning and found that my replication failed again for the same reason.  

Can anyoen tell me how to stop this from occurring again??  The first time this happened i had DNS settings on the iSCSI nic but not any longer. Any helkp is greatly appreciated.  Thanks!!

Watch Question

Do you have both networks on a seperate subnet and ip range? if they are on the same Ip range or subnet you can usually have some issues.
Also, try setting the dns on the internal network manually. Does the backup network have a dns server itself, and is it static ips?

Best option i think is to have both cards with static ip settings, the internal to have the dns server manually configured so its using a server on the internal network to lookup, also, have the backup nic set static with no dns server.

Also, check if any server names are duplicated on the seperate networks


Both nics are static IP.  The networks are on different subnets.  The backup nic doesn't require any DNS settings at all.  Everything on the backup server is done with IP address only.  No names.  

A way around it would be to put the records in the host file, then the server wont use the dns server for the lookup, this will stop the replication getting the wrong ip address's. Im just checking about doing this in DNS Server.
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Most Valuable Expert 2018

In the DNS server's properties dialog, remove the binding to the iSCSI NIC; a DNS server will by default register all NICs it's listening on.


Can you elaborate on remove the binding?  Not sure where you are referring.  I don't see any bindings unserd DNS properties.  Thanks
Most Valuable Expert 2019
Most Valuable Expert 2018

Start the DNS console, open the properties of the DNS server, set the "Listen at the following addresses" (or similar, not using an English version) to "Only the following addresses", and make sure only the LAN address is listed there.
Aegil has the right idea.  Modify your c:\windows\system32\drivers\etc\hosts file with the appropriate records and that will superceed DNS.
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