SBS 2008 DNS / internet problems

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larryBird44

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Client has a Dell T310 SBS 2008 box with 3 workstations running Windows 7 Professional.

Network is currently like this

Westell DSL Modem > Belkin Router (consumer crap) > Dell Powerconnect 2816 > server > workstations

I used the wizards on SBS to configure the internet, add the users, connect the computers, etc.

We are having intermittent internet problems. The only problem in the server SYSTEM eventlog is "Cannot connect to DNS server". At first I thought it was a server DNS issue so I changed the maxcacheTTL to 3 days. However, I noticed that I couldn't get into the Belkin configuration so I had to manually reset the router and everything worked fine. One thing to note is that the SBS server is handling DHCP and DNS, and in the router configuration there isn't an option to not use an alternate config or the ISP. Could this be causing the problem?

I don't do this as my day job, so I need some good fixes or things to look for. The fix right now is to power cycle the router.
 
Make sure that DHCP is turned off on the Belkin router.

What is the IP & DNS of your server set to?
 
LoStMaTt said:
Make sure that DHCP is turned off on the Belkin router.

What is the IP & DNS of your server set to?
Click to expand...

DHCP is turned off on the router. It still picks up DNS from the ISP though, since they are listed in the router summary.

IP/DNS set to 192.168.2.5
gateway 192.168.2.1

powerconnect 2816 switch is NOT set to managed mode.
 
Post the relevant event logs here.
Also, when you are having DNS problems, do the client workstations lose access to the internet, the server, or both? I.e. run ping tests to determine this from the client workstations.
 
Can't post the log right now. Workstations & Server lose internet. I'm thinking it's the router.
 
Did you run the " Connect To The Internet Wizard" From the SBS Console ?


J'
 
Check the DNS Fowarder settings in the DNS console and in DHCP make sure the only DNS address DHCP is handing out is the IP of the SBS server.

Also on the DNS settings for the servers nic change primary DNS to 127.0.0.1 and secondary to 192.168.2.5.

**Best guess without any logs or event id's**
 
If cycling your router fixes the issue then I would hazard a swag to say that is the culprit. I've had SBS 2008 do something similar but that was because IPv6 was disabled and it didn't like that.
 
Your primary DNS should be 127.0.0.1 or the IP of the server and the secondary should be your ISP's DNS server. I have to assume that 192.168.2.5 is the Belkin? That would explain your DNS failure when the router took a crap. Avoid using resources from that router as much as possible.
 
Protoform-X said:
Your primary DNS should be 127.0.0.1 or the IP of the server and the secondary should be your ISP's DNS server. I have to assume that 192.168.2.5 is the Belkin? That would explain your DNS failure when the router took a crap. Avoid using resources from that router as much as possible.
Click to expand...


Wrong. With an active directory domain you never want to set servers or workstations to anything except AD integrated DNS servers. To resolve names outside the local network you use the forwarders in the DNS server.
 
That may be best practice, but I've run into issues with DNS updating too slowly when only using the forwarders. Setting secondary DNS to an outside DNS server resolves this without causing any problems in my experience with Server 2003 - 2008 R2 including SBS 08.
 
Thanks so far guys. I'm bringing in another router (WNDR2700) of mine to see if a new router gets rid of the problem. If not, I'm honestly at a loss and will tell this guy to call MS Support. There's nothing crazy about the setup so it's kinda strange. When I get back I'll be able to post the event logs.
 
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