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We have an SBS 2008 server that keeps losing connection to the internet approx 2-3 times a day. It's a simple setup, BT Business Broadband ADSL to a Wireless Zyxel router to the server. Clients connect via WiFi from their laptops. Plugging ethernet in makes no difference, only a reboot of the router seems to bring everything back again.

I'm looking at the forwarders on the DNS properties page and they're timing out when trying to resolve the IPs. Currently there are two IPs in there, which has timed out and which has finally resolved to

We've been in there and replaced all media, installed a PCI NIC, have changed the router three times. There are no errors in the DNS event logs pertaining to what's going on.

We've also been on to BT who are adamant that it's not their end.

Could someone shed some light on what could be going on or where else to look in the configuration of the server?

Thank you.

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It seems like you might have found the problem already--slow responding DNS forwarders. Try taking the forwarders out of your DNS setup entirely; your server will use root hints to resolve DNS queries. It might be a little pokey at first as it resolves and caches common requests (, etc.), but after a day or two it should be fine.

If your connection problem goes away, you'll know it was an issue with the DNS forwarders. If not, you'll know the problem is internal.


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I would try a different DNS forwarder. For example we use opendns' servers for our SBS DNS forwarders:

Another option would be Google's DNS Servers:

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