Question : exchange 2003 inbound email

I am unable to recieve email in exchange 2003 server. My domain is puroflux.com. Mail server is mail.puroflux.com. Why is the mail connection timing out when sending to this domain?

Answer : exchange 2003 inbound email

What Are the Minimum Requirements for Inbound Mail Flow?
   
 • Exchange Server must have access to the Internet on port 25. This access should not be blocked by firewalls or other network settings. Anonymous connections should be allowed.

• The Exchange Server SMTP virtual server should be configured to use the default settings. For more information about configuring the Exchange Server SMTP virtual server, see Article 266686: How to Configure a SMTP Virtual Server, Part 1 in the Knowledge Base.

• The public mail exchanger (MX) resource record configured on your public DNS service should be accessible to all other Internet domains. The MX record should point to the Exchange server and must be identified before messages can be sent or received.

• Recipient policies must be configured and applied correctly. Recipient policies will stamp the SMTP virtual server and the recipient's mailbox with the correct e-mail address.

Check the result n let me know

Thanks
Kunal