Virtual SBS 2003 server dns problem?

We were given responsibility a while back for a club computer.  Everything was running fine until week before last.  It is an SBS 2003 server installed as a virtual server and we're using the Exchange for club officers with Outlook Web Access (not POP3).  The server also acts as a web server for the club domain and that is working fine.
We first noted that outgoing email que was filling up and not going out.  Couldn't find a reason.  
Incoming emails work; outgoing to others within the exchange work; outgoing to any external domain fails.
We can remote into it.  We did so and found that we could not get to the internet from IE on the server.  We also could not ping to outside addresses.  
We can find NO log errors.  
It looks like the DNS is not working.  Trying an nslookup to any external address says it is timing out on DNS resolution.  The server is using itself as a DNS.  There are 3 internal IP addresses listed .12, .11., & .8 with .8 listed as the DNS server.  We can ping to internal IP addresses; we can ping external IP addresses, but CANNOT ping external URL addresses (
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Raymond JansenCommented:
Are there any dns forwarders in your dns configuration?
Rob WilliamsCommented:
Doesn't sound like DNS is the route of the problem, since you "could not ping to outside addresses". Can you ping the gateway/router? How about the ISP's gateway, the one configured on the router?
The first thing you need to do is figure out which DNS servers are in use for external addresses.  Typically you will use the DNS servers of your ISP for all external addresses.  Once you have these, go into DNS on the SBS server.  (Administrative Tools - DNS).  Right click on your server, which should be the only server listed directly under the root DNS item, and click Properties.  On the Fowarders Tab enter in your ISP DNS addresses, and make sure any dead DNS servers are removed.

Usually a loss of functionality like this comes only when DNS server IP addresses change, which is not very common.  If a firewall or other settings have been changed it is more likely the problem.  If port 53 is blocked then DNS would fail as well.  (Both UDP and TCP should be open on 53 for DNS)

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HISEagleAuthor Commented:
When I went into the DNS Forwarders tab there were two ISP DNS server addresses.  I first rearranged them (put #2 as #1) and tested; everything worked.  I then put them back where they were and tested; problem returned.  Finally, I removed the one that had been #1; everything now works fine.  Thank you, r-jansen, for asking the question and RaymondPayne for giving me the exact route to check it out.
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