DNS Settings Drop

[J. W.]

I am using my Windows 2K server as a local DNS server for my intranet. I
also use it as my DHCP server. I set in DHCP my Win2K DNS server as the
primary server, and the IP of the DNS servers of my ISP. If I were to list
my DNS server last, then I wouldn't be able to pick up DNS names of my
intranet machines. So I had to list it first. Everything seemed to work fine
for a while. Then eventually, it came to the point that I could surf the net
fine, but if I try to enter the DNS name of a computer on my intranet ex:
http://www.mydomain.home as opposed to the IP address or computer name, it
would time out because it won't recognize the name. In order to resolve it,
I had to keep releasing the IP address and renewing it from the DHCP server.

So what I decided to do is to remove my ISP DNS server IPs from the DHCP
confiration altogether. Suprisingly, I was still able to ping public DNS
names even without my ISP's DNS IPs in my configuration. I must be confused
because I was thinking that it shouldn't work if I didn't have my ISP's DNS
IPs as part of the configuration of what the DHCP server is sending. What
I'm thinking now is that perhaps the name is being resolved via my D-Link
Router and that the router is forwarding DNS settings since it picks up my
ISPs DNS settings once it receives the dynamic address. So I think I've
figured that out.

But could someone explain why every machine on my network would periodically
loose the DNS settings for my local intranet?

 

[Jonathan de Boyne Pollard]

JW> I set in DHCP my Win2K DNS server as the primary server, and
JW> the IP of the DNS servers of my ISP.

Don't do that.

<URL:http://homepages.tesco.net./~J.deBo...nt-all-proxies-must-provide-same-service.html>

JW> I must be confused because I was thinking that it shouldn't work if I
JW> didn't have my ISP's DNS IPs as part of the configuration [...]

If your DNS server has direct IP connectivity to Internet, then
_it_ can perform, and will have been performing, query resolution.

It's not actually necessary to involve your ISP's DNS server at all;
and the way that it _would_ be involved, if it was, is as a forwardee,
with your own DNS server configured as a forwarder, not in your DNS
Client configurations.

<URL:http://homepages.tesco.net./~J.deBoynePollard/FGA/dns-server-roles.html#ForwardingProxy>

 

[Kevin D. Goodknecht]

In

I am using my Windows 2K server as a local DNS server for my
intranet. I also use it as my DHCP server. I set in DHCP my Win2K DNS
server as the primary server, and the IP of the DNS servers of my
ISP. If I were to list my DNS server last, then I wouldn't be able to
pick up DNS names of my intranet machines. So I had to list it first.
Everything seemed to work fine for a while. Then eventually, it came
to the point that I could surf the net fine, but if I try to enter
the DNS name of a computer on my intranet ex:
http://www.mydomain.home as opposed to the IP address or computer
name, it would time out because it won't recognize the name. In order
to resolve it, I had to keep releasing the IP address and renewing it
from the DHCP server.

So what I decided to do is to remove my ISP DNS server IPs from the
DHCP confiration altogether. Suprisingly, I was still able to ping
public DNS names even without my ISP's DNS IPs in my configuration. I
must be confused because I was thinking that it shouldn't work if I
didn't have my ISP's DNS IPs as part of the configuration of what the
DHCP server is sending. What I'm thinking now is that perhaps the
name is being resolved via my D-Link Router and that the router is
forwarding DNS settings since it picks up my ISPs DNS settings once
it receives the dynamic address. So I think I've figured that out.

But could someone explain why every machine on my network would
periodically loose the DNS settings for my local intranet?

Win2k domain uses DNS to store service and resource locations for your local
network. Your ISP's DNS cannot possibly do this because it knows nothing of
your local network. You must only use your local DNS in all machines for
DNS. You can optionally use your ISP's DNS as a forwarder (recommended) in
your local DNS, Win2k DNS will by default use its root hints to resolve
names it does not know.
300202 - HOW TO Configure DNS for Internet Access in Windows 2000
http://support.microsoft.com/default.aspx?scid=kb;en-us;300202&FR=1

 

[Michael Johnston [MSFT]]

Having your ISPs DNS server in the client's IP settings is the culprit for the problem. The clients may at anytime stop querying the local DNS server and start
querying the ISP. If that happens, then local names will no longer work. We always suggest only pointing to the internal DNS server for internal clients. Then
rely on this DNS server for Internet name resolution as well. The reason this works in your scenario is that out of the box, DNS includes a list of the root hint
servers for the Internet. Since the DNS server knows who the root servers are, it can resolve any Internet name needed. Forwarders can also be setup to the
ISP if you wish but it's not a necessary configuration step to get it working.

Thank you,
Mike Johnston
Microsoft Network Support
--

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