mail Flashcards
not fail exam 2
What protocol does mail use to send messages?
SMTP
What is a MTA?
Message transfer agent
How do emails get to their destination?
Routing through multiple MTAs
What is a UA?
Application that allows users to do stuff with emails
What are the two types of UAs?
Local and remote
What is a remote UA?
UA is an application on a device (laptop) that uses SMTP to send messages, and IMAP or POP3 to read messages.
When is authentication done for remote UAs?
Before mail is retrieved.
What is a local UA?
When the UA is the same computer as the MTA.
When is authentication done with local UAs?
With login
What is MIME?
Multipurpose Internet Mail Extensions
What is MIME used for?
UAs use it to display messages. Can display images, audio, even encrypt stuff! Basically makes emails more fun :) and wayyyyyy more sketch…
What do MTAs add to message headers?
Date/time
Email address
IP address
What is SMTP used for?
Usually clients sending commands across a server
What does the SMTP command HELO do?
Introduces yourself
What does the SMTP command EHLO do?
Requests extended mode and does what HELO does
What does the SMTP command MAIL FROM do?
Specifies the sender
What does the SMTP command RCPT TO do?
Specifies the recipient
What does the SMTP command DATA do?
Specifies the body of the message
What does the SMTP command RSET do?
resets
What does the SMTP command QUIT do?
Quits
What does the SMTP command HELP do?
Gets help about the session
What does the SMTP command VRFY do?
Verifies an address for you
What does the SMTP command EXPN do?
Expands an address
What does the SMTP command VERB do?
Verbose mode (more output probably)
What is POP3 used for?
Downloading email messages. Not great for multiple locations accessing it at the same time though.
What is IMAP used for?
Access messages (without removing them from the server usually). Usually fine with multiple locations.
What is a Sender Policy Framework (SPF)
Specifies who can send mail from the domain.
What is Domain Keys Identified Mail (DKIM)?
A way to detect mail spoofing.
Which ports are plaintext?
23, 25, 110, 993, 143, 587, 995
23, 25, 110, 143
What does STARTTLS do?
Tries to make insecure connections more secure. Doesn’t encrypt it end-to-end though…
