UNIT 10 - Email - SMTP Flashcards
What is the difference between SMTP and ESMTP?
SMTP is Simple Mail Transport Protocol.
ESMTP is Enhanced/Extended Simple Mail Transport Protocol.
SMTP can only send simple mails where as ESMTP can send more complex emails like those that have attachments.
What is the function of SMTP?
It is a protocol used to transport emails from a source to a destination.
What makes up a ‘Message Envelope’?
- From Address
- To Address
What makes up the ‘Email Header’?
- To Address
- From Address
- Other info found in DATA command (Time, subject, e.tc.)
Must the email addresses in the ‘Message Envelope’ and ‘Email Header’ be the same?
No they can be different.
This is useful for group emailing.
Can the final recipient see the contents of ‘Message Envelope’? Explain what information they can see.
No they can not.
However they can see the header information which will show all the different machines the email has passed through to get to them.
This can display info such as, time of each hop, machine name, machine IP, username and version number.
What happens if there does not exist an MX record for a specific domain?
It searches for an A record instead.
What are the three services in Linux Emails?
- MUA - Mail User Agent
- MTA - Mail Transfer Agent
- MDA - Mail Delivery Agent
What is MUA? And what are examples of this?
- The email ‘client’
- Used to read and send emails.
- Email received are collated into a mail box
- Emails that will be sent are passed to MTA.
- Examples include, ‘Pine’, ‘Mutt’, and ‘Mail’.
What is MTA? And what are examples of this?
- Equivalent of an ‘IP router’
- Takes messages from other MTA’s or MUA’s and passes them to other MTA’s or MDA’s.
- It adds own info with each hop
- Examples include, ‘qmail’, ‘sendmail’ and ‘postfix’.
What is MDA? What are local and network examples of this?
- Takes message from MTA and passes it to final user or another MTA
- Holds delivered message until MUA has read it.
- Example for local: Procmail and mail
- Example for network: sendmail.
