SMTP Flashcards
What does SMTP stand for?
Simple Mail Transfer Protocol
Which port is commonly used by SMTP for communication?
Port 25
What is the primary function of SMTP?
To send and relay email messages between mail servers
Which command is used to initiate an SMTP session?
HELO or EHLO
True or False: SMTP provides end-to-end encryption for email messages.
False. SMTP does not provide built-in encryption.
Which command is used to specify the email recipient(s) in an SMTP transaction?
RCPT TO
Which command is used to specify the sender of an email in an SMTP transaction?
MAIL FROM
What happens when an SMTP server encounters a temporary error (4xx response code)?
The email will be queued for delivery and retried later.
Which command is used to initiate the transfer of an email message’s content?
DATA
Which response code indicates a successful delivery of an email message in SMTP?
250
What is the difference between SMTP and POP3?
SMTP is used for sending email messages from the sender’s server to the recipient’s server, while POP3 is used for retrieving email messages from the recipient’s server to the recipient’s device.
What is the purpose of the SMTP “EHLO” command?
The EHLO (Extended HELLO) command is used to initiate an SMTP session and exchange information about supported extensions between the client and the server.
What are the main security concerns with SMTP?
Email spoofing, interception of messages during transmission, and unauthorized access to email servers.
What is SMTP relaying, and why is it important?
The process of transferring an email message between different mail servers. It is important for ensuring the reliable transmission of messages.
What is SMTP authentication, and why is it used?
SMTP authentication is a mechanism that requires users to provide valid credentials before sending email through an SMTP server. It is used to prevent unauthorized use of the server for sending spam or malicious emails.
What is a “mail delivery agent” (MDA) in the context of SMTP?
An MDA is responsible for delivering email messages from the recipient’s mail server to the recipient’s mailbox.
What is an SMTP “bounce” message?
A bounce message is an automated email response sent by an SMTP server to the original sender when it encounters a problem delivering the email to the recipient.
What is the purpose of the SMTP “STARTTLS” command?
The STARTTLS command is used to initiate a secure connection between the SMTP client and server using the Transport Layer Security (TLS) protocol.
What is the difference between SMTP and SMTPS?
SMTP operates on port 25 and does not provide inherent encryption, while SMTPS (SMTP Secure) operates on port 465 and uses SSL/TLS encryption for secure email transmission.
What is greylisting in SMTP and how does it work?
Greylisting is a technique used by some SMTP servers to combat spam. It temporarily rejects emails from unknown senders and requests the sending server to retry sending the email later. Legitimate servers will retry, while spam senders may not
Which TCP/IP layer does SMTP operate on?
Application layer
Which command is used to end the SMTP session?
QUIT
Which command is used to authenticate a client in SMTP?
AUTH
Which command is used to verify the availability of a recipient’s email address?
VRFY
Which command is used to start a secure encrypted connection in SMTP?
STARTTLS
Which command is used to abort the current mail transaction in SMTP?
RSET
Which command is used to relay an email message to another SMTP server?
TURN
What port does POP3 operate on?
Port 110
What’s the difference between HTTP and HTTPS?
HTTPS is more secure than HTTP because it uses encryption to protect information as it is being sent between clients and servers.
What is HTTP?
A method for transporting information between a web browser and a web server.
What port does SMTPS operate on?
Port 465
