A network administrator is tasked with blocking unwanted spam which is being relayed by an internal email server. Which of the following is the FIRST step in preventing spam that is originating from…

The correct answer is A. Closing off port 25 on the firewall. SMTP (Simple Mail Transfer Protocol) operates on port 25 and is the protocol used to send and relay email. Bots on the network use port 25 to connect to the internal mail server and relay outbound spam. Blocking port 25 on the firewall is the first and most targeted step, as it…

Network security

Question

A network administrator is tasked with blocking unwanted spam which is being relayed by an internal email server. Which of the following is the FIRST step in preventing spam that is originating from bots on the network?

Options

AClosing off port 25 on the firewall
BClosing off port 53 on the firewall
CTurning off the SMTP service on the email server
DTurning off the IMAP service on the email server

How the community answered

(21 responses)

A
71% (15)
B
14% (3)
C
10% (2)
D
5% (1)

Explanation

SMTP (Simple Mail Transfer Protocol) operates on port 25 and is the protocol used to send and relay email. Bots on the network use port 25 to connect to the internal mail server and relay outbound spam. Blocking port 25 on the firewall is the first and most targeted step, as it prevents bots from establishing SMTP connections to relay spam externally without disrupting the legitimate operation of the mail server for internal relay (which can use alternative ports like 587 for submission). Port 53 is DNS, and shutting down SMTP or IMAP services entirely would disrupt all email functionality.

Topics

#SMTP#port 25#firewall rules#spam prevention

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