the situation was, our email was hosted on a third party, that also manage our DNS.
we install on our network a exchange 2003 server. we ask our host to change the DNS to point the mx record directly to our network.
here is the infrastructure :
INTERNET --- FIREWALL ---- EXCHANGE 2003 Front (DMZ) --- FIREWALL ( SAME ) --- EXCHANGE 2003.
here is what happen, for outside person, we do not receive everything, we receive yahoo.com, we don't receive sympatico.com,
we can send to everybody.
I check the firewall for spaming, it's off. AntiVirus is off, In exchange, DNS check is not selected on both server.
what I suspect is that our host did not modify properly the dns and is relaying the message.
so I whant to verify our DNS over the internet to check for the MX record.
how can I achive that ?