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Windows 2008 DNS? Very slow internet

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  #1  
Old 22-09-2009
dor
 
Posts: n/a
Windows 2008 DNS? Very slow internet

We just installed a completely new Windows 2008 domain with 2 servers,
one running DNS. Everything is working great except the internet.
The pages come up but its soooo slow to load the pages. We checked
with ISP and all speeds are above normal.
What could be causing this…internal DNS problem?
We have DHCP enabled for all clients with the servers IP address being
handed out for DNS. The server is using itself for DNS and has all
static IP info in.
Any help would really be appreciated!!

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  #2  
Old 22-09-2009
Bill Grant
 
Posts: n/a
Re: Windows 2008 DNS? Very slow internet

No, it won't be DNS. DNS just resolves the URL to an IP. Once the client
machine has the IP address to connect to, DNS has no further part in it.
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  #3  
Old 22-09-2009
dor
 
Posts: n/a
Re: Windows 2008 DNS? Very slow internet

What about a DNS forwarder to ISP DNS?
Is there a doc out there with how Windows 2008 DNS should be setup?
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  #4  
Old 22-09-2009
Ace Fekay [MCT]
 
Posts: n/a
Re: Windows 2008 DNS? Very slow internet

I agree with Bill that DNS is not causing this, whether you setup a
Forwarder or not, but a Forwarder is recommended to offload resolution
processing to the ISP's DNS server.

As for the "slowness," that can be defined multiple ways and depends on your
setup. Describe your setup, such as do you have ADSL and the 2008 machine
has two NICs and is the NAT device, or is there a router and the 2008 has
one NIC, etc. Be descriptive, please. Also, is 2008 a DC?

Also post an ipconfig /all from the 2008 machine so we can evaluate the
config and make suggestions if necessary.
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  #5  
Old 22-09-2009
Rudolf Meier
 
Posts: n/a
You have to correct the setting for the dns forewarding. Alltough it should
not have such an influence (as mentioned by Bill and Ace) it still has...
the resolution is extremely slow, because your server always starts at the
root servers for every resolution. (we had the same problem after replacing
our dns server) ...

Often in the process of deploying a new server and DNS in an existing
environment, a bad DNS FORWARDER record gets left behind in your new DNS
server. The problem doesn't present itself until you decomission the old DNS
server. Your new DNS server is very slow with external DNS lookups because
it forwards requests to a DNS server that no longer exists. This process
eventually falls and finds and alternate DNS path for resolution.

To correct this problem look for and remove the "dead DNS forwarder" records
from your new DNS server.

Open the DNS manager,
right click on the DNS server and choose properties,
select the FORWARDERS tab,
remove and invalid DNS server forwarder records.

Resolution should be immediate without restart.
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  #6  
Old 01-11-2009
Ace Fekay [MCT]
 
Posts: n/a
Re: Windows 2008 DNS? Very slow internet

I wouldn't exactly put it that way. And I wouldn't call it a 'dead'
forwarder. It may not necessarily manifest itself when decommissioning a
server, rather it can manifest itself at any time.

If a DNS server that is set as a Forwarder is no longer functioning, or if
whomever owns the server decides to disable Recursion, which will make it
not respond to queries to zones it does not host (effectively making it a
content only server), or is controlling it by "views" ( a BIND feature to
control what subnets it responds to for queries), then the DNS service will
follow a time-out (TTL or Time to Live) algorithm when it sends the query to
the first Forwarder in the list. If there is no response (NULL response)
after the TTL, then it eliminate that Forwarder for this query only, and it
will then send the query to the next Forwarder in the list. If none of the
Forwarders respond, the DNS service will then send the query to the Root
Hints to devolve the query.

Now - and this is an important "now," if there are many DNS servers listed
in the Forwarders list, such as 3 or 4, the time out value for the number of
Forwarders listed may exceed the timeout (TTL) the client side resolver
service is set to by default (on the client machine making the request),
therefore receiving that familiar 'HTTP 404 not found' in the browser.

For practical purposes understanding the TTLs, I would suggest to never set
more than two Forwarders.

To find out if a DNS server will respond to queries and be eligible to be
used as a Forwarder, you can test it by using the nslookup utility (use
set -d2 option and look for 'recursion available' or 'recursion not
available'
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  #7  
Old 12-04-2010
Member
 
Join Date: Apr 2010
Posts: 1
Re: Windows 2008 DNS? Very slow internet

I have a similar problem. I have a Server 2008 Enterprise, internet router is connected directly tothe server and distributes to the network via routinga and remote acess. On ther server, speed tests display internet download at around 80MB, but on the network clients, it won't go faster than 9MB. What could it be?
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  #8  
Old 07-05-2012
Member
 
Join Date: May 2012
Posts: 1
Re: Windows 2008 DNS? Very slow internet

Quote:
Originally Posted by Rudolf Meier View Post
You have to correct the setting for the dns forewarding. Alltough it should
not have such an influence (as mentioned by Bill and Ace) it still has...
the resolution is extremely slow, because your server always starts at the
root servers for every resolution. (we had the same problem after replacing
our dns server) ...

Often in the process of deploying a new server and DNS in an existing
environment, a bad DNS FORWARDER record gets left behind in your new DNS
server. The problem doesn't present itself until you decomission the old DNS
server. Your new DNS server is very slow with external DNS lookups because
it forwards requests to a DNS server that no longer exists. This process
eventually falls and finds and alternate DNS path for resolution.

To correct this problem look for and remove the "dead DNS forwarder" records
from your new DNS server.

Open the DNS manager,
right click on the DNS server and choose properties,
select the FORWARDERS tab,
remove and invalid DNS server forwarder records.

Resolution should be immediate without restart.
While this wasn't the exact thing that was happening with me, i was having a similar problem.
I set the DC/DNS server up at home, and it automatically pulled in my gateway as the forwarder address. When i brought this into the office it was looking for the old (10.0.0.138) gateway which obviously could not be found. I deleted this entry and everything began to run smoothly once again.
I would like you to know that i registered on this site just to say thank you!
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