The relay agent on a mail server plays a role in spam prevention. Which of the following incorrectly describes mail relays?

A.
Antispam features on mail servers are actually antirelaying features.

B.
Relays should be configured “wide open” to receive any e-mail message.

C.
Relay agents are used to send messages from one mail server to another.

D.
If a relay is configured “wide open,” the mail server can be used to send spam.

Explanation:
B: Most companies have their public mail servers in their DMZ and may have one or more servers within their LAN. The mail servers in the DMZ are in this
protected space because they are directly connected to the Internet. These servers should be tightly locked down and their relaying mechanisms should be
correctly configured. If relays are configured “wide open” on a mail server, the mail server can be used to receive any mail message and send it on to the intended
recipients, thereby contributing to the distribution of spam. Therefore, mail relays should not be configured “wide open.”
+ A is incorrect because it is true that antispam features are actually antirelaying features. It is important that mail servers have the proper antispam features
enabled. Many companies also employ antivirus and content-filtering applications on their mail servers to try to stop the spread of malicious code, and not allow
unacceptable messages through the e-mail gateway. It is important to filter both incoming and outgoing messages. This helps ensure that inside employees are
not spreading viruses or sending out messages that are against company policy.
+ C is incorrect because it is true that mail servers use a relay agent to send a message from one mail server to another. This relay agent needs to be properly
configured so that a company’s mail server is not used by another for spamming activity. Spamming usually is illegal, so the people doing the spamming do not
want the traffic to seem as though it originated from their equipment. They will find mail servers on the Internet or within company DMZs that have loosely
configured relaying mechanisms and use these computers to send their spam.
+ D is incorrect because it is true that if a relay is configured “wide open” the mail server can be used to send spamand any other mail message it receives. This
means that the server can be used to distribute advertisements for other companies, spam messages, and pornographic material.