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MX Toobox reports Reverse DNS Fail but it appears correct

I have been having DNS issues since getting a different IP address about 5 days ago. MX Toolbox give a Reverse DNS fail while dnsstuff.com gives it a Reverse DNS authenticity: [Verified]

Now I know the real test is to wait for the client to send an email successfully that failed, but I am a little worried that it is an issue on my side. However, everything I read is that it is a ISP issue. All the DNS setting appear correct through ATT and I am getting a success from one site. Is the mxtoolbox wrong, or is there something I can check on my side?

I have a watchguard x750e firewall and an Exchange 2003 mail server.

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Papertrip

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DrDave242

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Papertrip

What DrDave said is all correct, but unless you tell nslookup to use an external server, those commands could just be seeing an internal view. For situations like this it's best to test from an external source.

DrDave242

If your internal and external domain names are identical, then yes, you will need to tell nslookup to use an external server (using the server <IP address> command). Otherwise, your server will send the query out to the public DNS anyway via forwarders or root hints.

ctrisdale

ASKER

Thanks guys. You are both correct. I got the correct record with my ISP and all is good to go. Thank you for your input