Welcome to the ITFreeTraining video on how to configure Forwarding and Conditional Forwarding
on Windows Server. By the end of this video you will be able to configure Windows DNS
to forward DNS queries to your ISP’s DNS server and use conditional forwarding to forward
DNS queries that the ISP’s DNS server cannot resolve to a DNS server that can. In order
to do this, I will change to my computer running Windows 8 and which has remote management
tools installed. First of all, I will open a command prompt
by opening charms, selecting search and then select the command prompt icon. Once the command
prompt is opened, I will attempt to ping the Domain Controller HighCostDC1. This will fail
as the DNS server will not know how to resolve DNS queries for this domain.
The DNS server for this domain is configured currently to resolve requests by contacting
the root hint servers. To make DNS queries more efficient, as shown
I will change the configuration of the DNS server to instead forward DNS queries to the
ISP’s DNS servers. Since the ISP’s DNS server resolves a lot of DNS queries there
is a chance the DNS query that is attempting to be resolved may have already been resolved
and is still in the DNS cache on the ISP’s DNS server.
In order to make the change, I will open server manager from the quick launch bar and then
from the tools menu select DNS. To change any settings for the server, right click the
server and select properties. Next I need to select the tab forwarders and
press the button edit. It is just a matter of entering in the IP Addresses of the ISP’s
DNS servers. Your local ISP should have at least two DNS servers for redundancy. Some
ISP’s will have more. Windows will attempt to contact these DNS servers after they are
entered and you should get an o.k. under the validated column. If this does not happen,
check that you have entered in the correct DNS servers and you do not have a firewall
blocking the connection. Now that the forwarders have been configured
I will go back to my command prompt and attempt to ping HighCostDC1 once again. As you can
see the, the request has failed again. As you can see here, the setup is that ITFreeTraining
and HighCostTraining are both forwarding their DNS requests to an external DNS server. Since
HighCostTraining ends in dot local, this address cannot be registered on the internet and thus
no internet DNS server will ever be able to resolve it.
To get around this, conditional forwards needs to be setup like this to forward all DNS queries
for HighCostTraining to the HighCostTraining DNS server and all other DNS queries to the
ISP DNS. To do this, I will go back to DNS Manager
and go down to the container Conditional Forwarders. To create a new conditional forwarder, right
click the container and select New Conditional Forwarder.
At the top, I need to enter in the DNS name that I want to forward, in this case the DNS
domain will be HighCostTraining.local. Under this I need to enter in the DNS server or
servers that can resolve queries for this domain.
Notice that DNS manager will attempt to resolve the address. Remember that the DNS query will
be sent to the local ISP DNS server so the request will not be able to be resolved so
this error can be ignored. At the bottom is the tick box, “Store this
conditional forwarder in Active Directory, and replicate it as follows:”. This will
store this forwarding rule in Active Directory and thus will be used by other DNS servers
in the domain that are installed on Domain Controllers.
Notice that when this option is ticked, I can also select which DNS servers this rule
will be forwarded to. By default this conditional forwarder will be used by all DNS servers
in the forest. I can also select to use this only in the domain or the last option, to
use an option that is compatible with Windows Server 2000.
In this case, I will leave it on the default setting of the forest and press o.k. Now that
the conditional forwarding is configured, I will go back to the command prompt and try
and ping HighCostDc1. You will notice that Windows will not be able to resolve the DNS
name. This is a problem that you may often have
when troubleshooting DNS problems. In this case, this DNS request is cached in the local
cache that it is not resolvable. In order to resolve, I need to first clear the cache.
To do this, run the command IPConfig /FlushDNS. Once the DNS cache has been cleared, notice
that when I run the command again, this time the IP Address of the HighCost Domain Controller
can be resolved. You can see that by using a combination of forwarding and conditional
forwarding you can achieve a good result on your network.
Thanks for watching this video from ITFreeTraining. I hope you found this video informative. For
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time.