Domain controller

mcrmg
mcrmg used Ask the Experts™
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Hi,

I have two dcs, one is supposed to be the backup when the main one goes down.  I want to setup so when the main one goes down, internet will be still up.  But on the bakup dc, there is no DNS??!! (not in administrative tools)

any ideas?  thanks
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Commented:
You would need to install DNS on the second DC. It would pull the zone information automatically if the primary DC is using an AD integrated zone. Once this is done you would need to update your DHCP scope to pass out the 2nd DC's IP as the secondary DNS. You would also need to update static IPs with that IP.

Commented:
Ideally you should have installed DNS server while installing the DC. You can try to telnet your secondary DC's port 53 and see whether it is running or not.

If it is running, you can access the DNS server from the primary server's DNS SNAP IN.

You should configure forwarder for internet DNS in both the DNS servers and use both the DNS server's IP in all the client computers so that once Primary DNS is unavailable, it goes to the secondary and there you have the proper DNS forwarder for internet browsing.

Hope this will help.
You would need to add DNS:
Add Remove Programs
Add/Remove Windows Components
Netowrking Services, and then hit Details
Add Domain Name System

Make sure that your backup DC is also not the primary for the DNS.  You'll want this DNS to get updates from your primary.  I haven't done much in a while in this area so you may want to await further input on the configuration of DNS from someone else.
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Commented:
You need to install DNS.  Add and remove programs: windows components: network services: DNS

Author

Commented:
I installed dns and dhcp, when I turn off the primary, it says domain is not available.  How can I provide infomation foor EE to help?>  thx
Is your nic on your Backup configured to look at itself for DNS resolution?

Author

Commented:
on the backup one, the dns on nic is looking at the main one and itslef  thx

Author

Commented:
this is what i found out. I use logmein to remote.  when backup reboots, I can stillhave internet.

but when primary boot up, i can still remote the server, but no internet...

it looks like i have connection, but no internet...thx

Author

Commented:
in the backup dns forwarders, do i need to add external dns? now is empty..thx
Yes you have to have the forwarders

Author

Commented:
I should use the same forwarder as in primary. Right?  Thanks
Only if they are at the same physical location.

Author

Commented:
yes, they are, right now I have the same forwarder in both dns.

I have turned off the primary one, from the backup, i have the internet.  but from other server, i dont, but I can ping , say, yahoo.com....i checked the options in IE...it looks fine.  thanks

Author

Commented:
Here is the update, after rebooting backup dc (primary is off), other pc has no internet nor can ping. Plx help. Thx
When you say the other server you don't.. Do you mean the other servers/workstations that "should" utilize your backup dc for dns as well are not?  If so have you updated your dhcp server to handout the dns address of your backup as a secondary dns?  And any machine that does not use dhcp but has a static ip, do they have the backup's ip for their secondary dns?

Author

Commented:
okay, here is the update.

It doesnt matter which dc I unplugged, internet is still up.

But if I reboot a pc, I dont get internet because it is looking for the dhcp from the primary, if I turn off primary...thanks

Author

Commented:
right now the dhcp in backup is red...i think that;s why, how can I turn it on when the primary goes down?  thanks
I am almost certain that it is not an automatic process.  I would start the service only when the primary is not running.  If you have the DHCP snap-in up then you'll need to just rt click on the DHCP server, All Tasks, Start.  If that is I'm reading into what you are saying is accurate.  

Author

Commented:
okay, it works by selecting start, now it is active but what if primary comes back up? do I have to stop dhcp on backup?  thanks
You don't HAVE to, but I would suggest it.  I'm sure there's differing opinions out there on this.  And I'm not CERTAIN of the best practice, but my gut tells me that you should only have the DHCP running on the primary and only start the DHCP on the backup if it's needed.  Reason being that if you have to work with the DHCP server you only need to work with one instead of trying to manage two at once.

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