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DNS Frwarding stalls out and mail flow stops

I guess I am asking for hints on how to set up DNS and forwarding. I have two main servers running DNS. Server 1 (Primary) uses Server 2 (Secondary) as its DNS and Secondary uses Primary for its DNS. And the whole domain uses Primary as it DNS to include Exchange 2003. I set up the following Forwarders on the Primary server..

146.145.64.2
4.2.2.2
65.106.1.196
146.145.64.3
65.106.7.196
4.2.2.1

Sometimes all mail flow will stop and we will get errors like " Relay access denied". I run a nslookup for a domain like www.google.com and it fails. I will go into the DNS Server properties and move a different server to the top of the list, restart the DNS services and mail starts to flow. Round Robin is enabled, forward time out is 5. Shouldnt forwarding lookups go through all the servers I have listed before failing?

CharliePete00

If you're using Exchange 2003 I'm guessing this is an AD domain environment right? And that your DNS servers are also DCs? All name resolution for all internal computers is handled by the DCs right?

If so I'd recommend the following for your network.

For your network clients:
1. Use only your 2 DCs as DNS servers

For your DCs:
1. Make each DC its own primary DNS server and the other DC as the secondary
2. Remove all DNS forwarders and let the DC resolve name via root hints
OR
2. Configure your ISPs DNS server as the only forwarder

thelink12

ASKER

I ended up removing DNS from the problematic server, all traces of DNS from the file system, rebooted, reinstalled DNS and so far everything is working well.

ASKER CERTIFIED SOLUTION

DarthMod

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