Exchange 2007 uses direct DNS for all outgoing mail.
Mail that is sent from our public IP (1.2.3.4 – this is the IP of my mailserver) is delivered to the spam folders for providers such as Comcast and yahoo.
Currently, our SPF looks like this:
v=spf1 ip4:1.2.3.4 mx a:mail.domain.com ?all
MX: mail.domain.com.(10)
The reverse DNS entry on our ISP is mail.domain.com for our IP
The banner HELO response from our server is <220 mail.domain.com>
Our IP address is NOT blacklisted anywhere, and the Cisco Senderbase gives us a score of Good
What is the reason our mail doesn't look legit?
Best Answer
if i get this straight:
your domain is registered to the mailservers of your provider and your mailserver is delivering the mails directly. So when the mail is delivered the reverse lookup of the ip can faile (1st spam hit), then the receiving mailserver sees an spf that is not pointing to your system (2nd spam hit) and your system is only listed as IP address in SPF record (maybe spam hit #3) and the incoming direction is routed via a different system, which is not 100% clear by the information you gave (spam hit #4).
This also explaines why it's working when you try to deliver mail via the web interface.
Just tell your exchange box to send all outgoing mail via the providers smtp server and everything should be fine again.
KR,
gromit