am new in this forum, but hope to participate regularly.
I currently ran into a strange problem, which I have difficulties to explain.
One of our clients have an email domain like company.com.xx where xx is the country code.
Since we are unhappy with our local provider, we recently moved that domain to a provider in the US.
The US provider setup new MX records and most DNS queries resolve correctly to these new MX records.
However, sometimes the query resolves to the old IP addresses.
The mail server has the hostname company.com.xx which is the same as the email domain name. I know that this does not make sense but this is how it is configured.
The mail server also is connected to the Internet with two public IPs. Again, I know that is not good, but that is how they have it currently.
Now my theory is that if a DNS query resolves the MX record for company.com.xx correctly the mail are delivered to mail hoster in the US, which is how it should be. However, if the MX record for company.com.xx cannot be resolved, the DNS query looks for the A reord of company.com.xx and then delivers to the public IPs connected to the server. Which has as hostname company.com.xx.
What I would like to know, does my theory make sense? Is that how it could be? How can I confirm this?
Thanks a lot for your commments.