Some External Sites cannot be access

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Charles

I am running SBS2000 with AD and 7 XP Pro Clients. I have
configured DDNS and all clients workstations have no
problems registering. All network connectivity is working
however, user have reported they cannot access some web
sites and at other times they can even though Inetrnet
access is working fine. It only happens on some web sites
50% of the time then all seems to work ok.

I have configured forwarders in DNS to the ISP to resolve
external addresses. The server IP config is
192.168.10.5/255.255.255.0 and gateway is 192.168.10.1.
I have configured the server DNS to itself in accordance
with Microsoft recommendations on DNS config for TCP/IP.

Does anyone know what else might be causing this
intermittent problem????

Please help
 
In
Charles said:
I am running SBS2000 with AD and 7 XP Pro Clients. I have
configured DDNS and all clients workstations have no
problems registering. All network connectivity is working
however, user have reported they cannot access some web
sites and at other times they can even though Inetrnet
access is working fine. It only happens on some web sites
50% of the time then all seems to work ok.

I have configured forwarders in DNS to the ISP to resolve
external addresses. The server IP config is
192.168.10.5/255.255.255.0 and gateway is 192.168.10.1.
I have configured the server DNS to itself in accordance
with Microsoft recommendations on DNS config for TCP/IP.

Does anyone know what else might be causing this
intermittent problem????

Please help
Click to expand...

Are you running ISA on the server?
Is the server mutli homed?
What DNS is being used for your Forwarder?

--
Regards,
Ace

Please direct all replies to the newsgroup so all can benefit.
This posting is provided "AS IS" with no warranties.

Ace Fekay, MCSE 2000, MCSE+I, MCSA, MCT, MVP
Microsoft Windows MVP - Active Directory
 
In
Charles said:
I am running SBS2000 with AD and 7 XP Pro Clients. I have
configured DDNS and all clients workstations have no
problems registering. All network connectivity is working
however, user have reported they cannot access some web
sites and at other times they can even though Inetrnet
access is working fine. It only happens on some web sites
50% of the time then all seems to work ok.

I have configured forwarders in DNS to the ISP to resolve
external addresses. The server IP config is
192.168.10.5/255.255.255.0 and gateway is 192.168.10.1.
I have configured the server DNS to itself in accordance
with Microsoft recommendations on DNS config for TCP/IP.

Does anyone know what else might be causing this
intermittent problem????

Please help
Click to expand...

What DNS servers are the clients using?
 
Verify if name resolution is the culprit. On a client that cannot access the Internet, open a command prompt and type
NSLOOKUP. It should default to your internal server as this is the only server that the clients should point to for DNS. At the ">"
prompt, type the name of the site you are trying to access followed by a period ".". Does this resolve? Does it resolve to the
correct IP address? To verify, go to www.dnsstuff.com and search for the same name. Compare the results. They should be
the same. If not, the problem could be DNS cache pollution.

Thank you,
Mike Johnston
Microsoft Network Support
--

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which they originated.
 
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