SMTP quiz

MDA: Mail Delivery Agent

A mail delivery agent or message delivery agent (MDA) is a computer software component that is responsible for the delivery of e-mail messages to a local recipient's mailbox. Also called an LDA, or local delivery agent.

MX record

A mail exchanger record (MX record) is a type of resource record in the Domain Name System that specifies a mail server responsible for accepting email messages on behalf of a recipient's domain, and a preference value used to prioritize mail delivery if multiple mail servers are available.

MUA : Mail user agent

A mail user agent (MUA) is a program that allows you to receive and send e-mail messages; it's usually just called an e-mail program. To use an MUA such as Eudora or Microsoft Outlook, you install the MUA program on your computer and then use it to download and store e-mail messages to your computer; it will also allow you to read or write messages offline. Web-based MUAs, such as Hotmail and Yahoo, store messages on their own mail servers and allow access to them through a Web page. An MUA is sometimes called an e-mail agent or an e-mail client.

PKI

A public key infrastructure (PKI) is a set of roles, policies, and procedures needed to create, manage, distribute, use, store, and revoke digital certificates and manage public-key encryption.

Smart host

A smarthost is a mail relay that is specialized to deal with outbound email. If you have a private LAN, you may want to control the flow of outbound email, and prevent "any old server" from being able to deliver email to the internet, or perhaps your internal systems only resolve internal DNS and can't resolve hosts or domain MX records for systems "out there on the interwebs". In a case like this, you might designate a single host as the Smarthost. All the other machines would in turn blindly send any outbound email to the Smarthost. The smarthost would have the ability to resolve hosts and domain MX records on the internet, and would be permitted by firewall/acl/iptables/whatever to communicate to other hosts on port 25, or port 587, to deliver outbound email.

How an email is sent?

A user (Alice) sends an email message and connects to an SMTP (Simple Mail Transfer Protocol) server as configured in her email client or Mail User Agent (MUA). On the SMTP server, a Mail Transfer Agent (MTA) looks at the recipient address and looks up the domain part of the address to determine its destination.

Email Protocols: IMAP, POP3, SMTP and HTTP

Basicaly, a protocol is about a standard method used at each end of a communication channel, in order to properly transmit information. In order to deal with your email you must use a mail client to access a mail server. The mail client and mail server can exchange information with each other using a variety of protocols.

What is delivery agent?

Delivery Agent is a provider of shopping-enabled entertainment for television shows, movies, magazines, sports, and music videos. Delivery Agent help to create the market for shopping-enabled entertainment by redefining how products seen on or related to entertainment content are catalogued, sold and measured online.

Install dovecot-imapd

Dovecot is a Mail Delivery Agent, written with security primarily in mind. It supports the major mailbox formats: mbox or Maildir. It is a simple and easy to install MDA. This guide explains how to set it up as an IMAP or POP3 server. "apt-get install dovecot-imapd"

exim4

Exim4 is another Message Transfer Agent (MTA) developed at the University of Cambridge for use on Unix systems connected to the Internet. Exim can be installed in place of sendmail, although the configuration of exim is quite different to that of sendmail.

mailutils

GNU Mailutils is a rich and powerful protocol-independent mail framework. It contains a series of useful mail libraries, clients, and servers. These are the primary mail utilities for the GNU system. The central library is capable of handling electronic mail in various mailbox formats and protocols, both local and remote. Specifically, this project contains a POP3 server, an IMAP4 server, and a Sieve mail filter. It also provides a POSIX `mailx' client, and a collection of other handy tools. The GNU Mailutils libraries supply an ample set of primitives for handling electronic mail in programs written in C, C++, Python or Scheme. http://mailutils.org/manual/mailutils.html#SEC1

IMAPS

IMAP over SSL (IMAPS) is assigned well-known port number 993.

Remote Email Clients

In Internet, an email client, email reader or more formally mail user agent (MUA) is a computer program in the category of groupware environments used to access and manage a user's email. Client is meant to be a role. For example, a web application which provides message management, composition, and reception functions may internally act as an email client; as a whole, it is commonly referred to as webmail. Likewise, email client may be referred to a piece of computer hardware or software whose primary or most visible role is to work as an email client.

IMAP = Internet Message Access Protocol

In computing, the Internet Message Access Protocol (IMAP) is an Internet standard protocol used by e-mail clients to retrieve e-mail messages from a mail server over a TCP/IP connection. IMAP is defined by RFC 3501. ... IMAP over SSL (IMAPS) is assigned the port number 993. email is stored and managed on remote server

POP = Post Office Protocol

In computing, the Post Office Protocol (POP) is an application-layer Internet standard protocol used by local e-mail clients to retrieve e-mail from a remote server over a TCP/IP connection. Downloads mail to your local computer

What are SMTP relays and smarthosts?

In general, both are mail relays, and a mail relay is just a server that passes mail to another mail server, via SMTP, rather than a server that offers mailbox service to end users via POP3/IMAP/HTTP.

mbox format

MBOX stands for MailBOX. The MBOX file is the most common format for storing email messages on a hard drive. All the messages for each mailbox are stored as a single, long, text file in a string of concatenated e-mail messages, starting with the "From" header of the message. MBOX files were used predominantly on Unix.

By default, the IMAP protocol works on two ports:

Port 143 - this is the default IMAP non-encrypted port Port 993 - this is the port you need to use if you want to connect using IMAP securely

By default, the SMTP protocol works on three ports:

Port 25 - this is the default SMTP non-encrypted port Port 2525 - this port is opened on all SiteGround servers in case port 25 is filtered (by your ISP for example) and you want to send non-encrypted emails with SMTP Port 465 - this is the port used, if you want to send messages using SMTP securely

What is post fix?

Postfix is a free and open-source mail transfer agent (MTA) that routes and delivers electronic mail, intended as an alternative to the widely used Sendmail MTA. Postfix is released under the IBM Public License 1.0 which is a free software license.

What is postfix?

Postfix is a free and open-source mail transfer agent (MTA) that routes and delivers electronic mail, intended as an alternative to the widely used Sendmail MTA. Postfix is released under the IBM Public License 1.0 which is a free software license.

What is SMTP?

SMTP is part of the application layer of the TCP/IP protocol. Using a process called "store and forward," SMTP moves your email on and across networks. It works closely with something called the Mail Transfer Agent (MTA) to send your communication to the right computer and email inbox.

What is a SMTP relay?

SMTP relays let you send emails through our servers using third-party clients, such as Microsoft Outlook®. To prevent spam, we limit our email accounts to 250 SMTP relays per day. This lets you send 250 emails from your email address on a daily basis.

What is a smart address?

Smart Address is a feature that allows users to run one label or letter report to individuals, mailing some at their work (or other organisation) and some at home.

Application layer protocol

The application layer abstraction is used in both of the standard models of computer networking: the Internet Protocol Suite (TCP/IP) and the Open Systems Interconnection model (OSI model)

MTA: Mail Transport Agent

The mail server works in conjunction with other programs to make up what is sometimes referred to as a messaging system. A messaging system includes all the applications necessary to keep e-mail moving as it should. When you send an e-mail message, your e-mail program, such as Outlook or Eudora, forwards the message to your mail server, which in turn forwards it either to another mail server or to a holding area on the same server called a message store to be forwarded later. As a rule, the system uses SMTP (Simple Mail Transfer Protocol) or ESMTP (extended SMTP) for sending e-mail, and either POP3 (Post Office Protocol 3) or IMAP (Internet Message Access Protocol) for receiving e-mail.

Simple Mail Transfer Protocol

Used for the delivery of electronic messages (email) and Designed for text-only

What is an MTA in email?

Within Internet message handling services (MHS), a message transfer agent or mail transfer agent (MTA) or mail relay is software that transfers electronic mail messages from one computer to another using a client-server application architecture.

System mail name

follows the @ part of address

Mail box: storage for messages

mailbox-format is a tag identifying one of the formats described at Mailbox Formats. path is the path to a directory where the mail is stored. This must be an absolute path, not a relative path. Even if relative paths appear to work, this usage is deprecated and will likely stop working at some point. Do not use the home directory, for reasons see Home vs. mail directory

Install Exim4

sudo dpkg-reconfigure exim4-config General type of mail configuration: internet site; mail is sent and received directly using SMTP System mail name: {DOMAIN} IP-addresses to lsiten on for incoming SMTP connections: 127.0.0.1 ; ::1 Other destinations for which mail is accepted: [EMPTY] Domains to relay mail for: [EMPTY] Machines to relay mail for: [EMPTY] Keep number of DNS-queries minimal (Dial-on-Demand)? <No> Delivery method for local mail: mbox format in /var/mail/ Split configuration into small files? <No>