What should you do to ensure that users can receive e-mail messages from the internet?

You are the Exchange administrator for your company. The network consists of a single Active Directory domain.

Exchange Server 2003 is implemented as the company wide messaging system. The relevant portion of the network is configured as shown in the exhibit:

Server1 is configured as a front-end server and as an incoming SMTP relay. It also hosts Microsoft Outlook Web Access, which is used by Internet users to access company e-mail.

Users stop receiving e-mail messages from the Internet. You use the DNS name and IP address to send test e-mail messages directly to Server1 from the Internet.

However, your e-mail messages are simply queued on Server1 along with a large number of other messages.

You need to ensure that users can receive e-mail messages from the internet.

What should you do?

A.
Configure the external DNS mail exchanger (MX) resource record of the e-mail domain to point to server1.

B.
Configure the internal firewall to allow server1 to communicate with the Exchange server and the global catalog server.

C.
Configure the default SMTP virtual server on Server1 to use the Exchange server as a smart host server.

D.
Configure the default SMTP virtual server on server1 to deliver all e-mail messages that have unresolved recipients to the Exchange server.

Explanation:
Server1 is not able to see either the back-end Exchange Server or the Global Catalog
server. Opening the appropriate ports on the internal firewall should resolve the problem.

Incorrect answers:
A: Mail is being received by Server1, hence the MX record must exist and be correct.
C: Since no SMTP traffic is passing between the servers, setting up a smart host on Server1 will not work.
D: Messages sitting in the queue on Server1 have recipients. Therefore, this answer can’t be correct.
Note that the users state that they are not receiving e-mail.
If the messages had no recipient, the users would not be aware that they were not getting their messages.