dhcp for virtual machines

I have a question I have 3 esx hosts on 1 host I have a dc doing dns my router does dhcp

so I want my vm's to use the dc dns and all others use my router

what I do at the moment is give the vm a static dns 1st to my router and 2nd to my dc so over 1 they get out to the net and on 2nd they can do domain stuff as if I dont have the 2nd dns pointing to my dc I cannot join the vm's to the domain for instance

so how can I do this automatically
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On the Virtual Machines, you should keep them static and point their DNS to your AD/Domain Controller DNS.  There should be ONLY one entry to that DNS Server.  Once set, do an IPConfig /flushdns and you will be able to join the DNS.

On the AD/DNS create a DNS Forwarder to your outside DNS servers for Internet Resolution.  That is done simply in the DNS program, right click the server and find Forwarder.  You can put in external DNS Servers or even an internal DNS.  Anytime a system queries the DNS and can't find the host, the forwarder will relay to the next DNS server.  This allows you to control the DNS for internal systems and even redirect a host to an internal ip.  Very useful to convert something like "mail.xxxx.com" to an internal IP address behind a firewall instead of pushing it out to the Internet."  

If I understand your scenario, this will allow you to have:

1) Join the domain from VM machine
2) Access external sites from VM w
3) Find internal systems/sites within the AD/DNS
4) Allow your router assigned DHCP systems to continue to use external/internal DNS

As for DHCP, you can leave it on the router and hand out internal DNS or external DNS.  However, to worktations that need to join the domain you should always use the DNS on the AD or you will have slow login!  In other words, make the DHCP server hand out the internal AD ip address that you added DNS Forwarders.  

If that DNS server should fail, you can always change dhcp to use an external DNS to keep the users surfing while you are repairing.

Please reply back if I did not understand the scenario.

Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
I would recommend, you disable DHCP on your router, and add DHCP role to your Server.

DNS and DHCP can be then integrated on your servers.

and then setup DNS forwarders to point to your ISP DNS servers beyond on the internet.

The only item, on your server DHCP server specify the routers IP addressbas the Default Gateway.

The issue with domain joining is your router is not AD integrated.

if you still wanted to use your router for DNS and DHCP, program the router to issue DNS IP address of your DC.

Configure DC DNS as forwarders to either router IP address or better your ISP IP DNS servers.
IanThAuthor Commented:
I was hoping to have a different dns setting inside the vm's only

the dc is not on most of the time its on my vsphere lab I am getting in to wds

what is the dns inside vmware for if I could just use 2nd dns ie dc in the esx host that would mean only the vm's using the dc dns
wouldn't that work?
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
ESX has no DNS. ESX is a host server that hosts your VMs, it does not play any role in offering DNS requets.

the settings on a host server are to configure for your DNS servers on your LAN.
IanThAuthor Commented:
ee dns
so if I just use my dc inside the host would that work
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
I do not know, what you are trying to achieve here?
IanThAuthor Commented:
just my vm are on the domain nothing else
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
use your DC DNS.
IanThAuthor Commented:
I dont get you ?
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
just my vm are on the domain nothing else

use your DC DNS.
IanThAuthor Commented:
but when I build a new vm from wds wont it need to have the dc dns done manually then
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
if you want VMs to be part of your domain and register with your domain, you must use a Windows DNS (Active Directory Domain Controller if Integrated)

if a client connects and uses a non Windows DNS, and a Router is not a true DNS, it's just a Proxy DNS, that proxys the request upstream to your ISP DNS.

Domain Join is likely to fail, because it will not find the SRV DOMAIN records, because a Router is not a DC.

ESX cannot do anything to help with this, it's not a VMware ESX issue.

My advice

1. When DC is UP and running in your lab, re-configure the router to issue DC IP Address as DNS, use DNS forwarders.

2, When DC is Down, reconfigure Router DHCP, to issue it's IP as DNS.

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IanThAuthor Commented:
actually couldn't that be done from wds to set dns and joinjom or is that always going to be manual step
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
It's possible.
IanThAuthor Commented:
asking new question for thanks andy
IanThAuthor Commented:
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