Inbound mail should be filtered for spam before it reaches users' mailboxes. Which service does that filtering?
Select an answer to reveal the explanation.
Short Explanation
The mail should pass a checkpoint that throws out the junk before people open it. You put a spam gateway on that path. A web balancer, a file cabinet, and a clock source do not read the mail.
Full Explanation
A spam gateway filters mail and keeps spam from landing in users' mailboxes. That is the service this path needs. A load balancer spreads traffic across servers. It does not inspect mail. A file server stores files. It is not a mail filter. An NTP server synchronizes clocks. It does not drop spam. Exam caveat: the gateway has to see the mail, which means the domain's mail exchange points at it or the mail passes through it. A filter that is not in the path cannot help. Operational check: send a known spam test the gateway is supposed to catch, and confirm it does not arrive in the mailbox. Check the quarantine so a wanted message can be released without turning the filter off. Record the result on the ticket.