DNS Server Problems - Keep having to restart the DNS service

[eggedd2k]

For about a week now during the day our office internet connection goes
down. When it goes down I have to restart the DNS service on our server
which brings the internet back online.

Our DNS server has forwarders set-up to send external requests to an
external internet based DNS server. We use NAT to share internet access
throughout the office.

When the connection goes down we can access websites by using IP
address. This obviously confirms the problem is DNS based.

Whilst restarting the DNS service on our server sorts the problem I do
need to find out what's causing it to go down.

There are no errors or warning messages in the event log.


Any advice welcomed!

 

[Herb Martin]

For about a week now during the day our office internet connection goes
down. When it goes down I have to restart the DNS service on our server
which brings the internet back online.

The "Internet" is NOT offline -- if it as you describe -- but rather
there seems to be a name resolution problem. It is very important
to accurately access such problem to be most effective when
troubleshooting them.

Our DNS server has forwarders set-up to send external requests to an
external internet based DNS server. We use NAT to share internet access
throughout the office.

Most likely unrelated.

When the connection goes down we can access websites by using IP
address. This obviously confirms the problem is DNS based.

Seems to do so. It could in theory be NAT issue that only affects the
DNS Server but this is unlikely.

You can test/confrim/disprove this by using a direct NSLookup command
while SPECIFYING the DNS Server IP to use:

nslookup www.google.com DNS.Server.IP.Address

Use this from the DNS server command line, specifying the
IP address of each and ever forwarder you have listed.

(You might also try this from a client, specifying each of the internal
DNS and the forwarder directly so as to look for differences.)

Curious: Do you have "Do Not use Recursion" checked on the
Forwarding tab (most of the time this is a good idea)?
But by changing this you may find you get different results (problem
might become permanent or more frequently if you are totally
dependent on the ISP DNS -- again, this isn't "fix" but a way to
look for more differences.

Whilst restarting the DNS service on our server sorts the problem I do
need to find out what's causing it to go down.

There are no errors or warning messages in the event log.

What version of Windows Server (you posted in Win2000), and what
is your "Service Pack" status -- generally all service packs and hotfixes
should be applied to Windows Servers.

You might also (strongly) consider a REPAIR install (from the original
CDROM) using install to the same directory AND ENSURING you
both receive the prompt to repair and confirm that.

 

[eggedd2k]

do not use recursion is NOT ticked. when the dns service fails no
events are logged. a simple service restart brings it back online.

 

[eggedd2k]

do not use recursion is NOT ticked. when the dns service fails no
events are logged. a simple service restart brings it back online.

 

[Herb Martin]

do not use recursion is NOT ticked. when the dns service fails no
events are logged. a simple service restart brings it back online.

I would tick it and see if it gets worse. It probably should be ticked
anyway. But if it gets worse (like fails all the time) then perhaps the
forwarding is failing all of the time.

 

[Ace Fekay [MVP]]

In

For about a week now during the day our office internet connection
goes down. When it goes down I have to restart the DNS service on our
server which brings the internet back online.

Our DNS server has forwarders set-up to send external requests to an
external internet based DNS server. We use NAT to share internet
access throughout the office.

When the connection goes down we can access websites by using IP
address. This obviously confirms the problem is DNS based.

Whilst restarting the DNS service on our server sorts the problem I do
need to find out what's causing it to go down.

There are no errors or warning messages in the event log.


Any advice welcomed!

I assume that the DNS server is multihomed. (On another hand, I hope that it
is not a DC for multihomed DCs can cause other issues). I've seen this
happen when any one of the NICs that DNS is set to use goes asleep, such as
if one of the NICs is connected to a PPPoE device (Weastell DSL modem). When
the modem falls asleep, so does DNS, then you'll need to restart the
service.

Try setting the modem to keep the connection 24/7, otherwise (recommended
anyway) is to disable one of the NICs, and get an inexpensive Linksys
Cable/DSL router and connect that to the modem and let it keep the
connection connected 24/7. Plug your DNS server into the switch and you're
good to go.


--
Ace
Innovative IT Concepts, Inc (IITCI)
Willow Grove, PA

This posting is provided "AS-IS" with no warranties or guarantees and
confers no rights.

Ace Fekay, MCSE 2003 & 2000, MCSA 2003 & 2000, MCSE+I, MCT, MVP
Microsoft MVP - Directory Services
Microsoft Certified Trainer

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