Which Type of Server Would Support the SMTP

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Which Type of Server Would Support the SMTP?

• Chances are, most of you reading this guide are
  already familiar with the most commonly used
  communication technology. But have you ever
  wondered how it works? In this article, we will
  learn how this service works and what is POP3,
  SMTP, IMAP and which type of server would
  support the SMTP.
• Mail Server Assignment
• Methods for fast message transmission began to be
  developed back in the early 60s of the XX
  century, and over the past time, certain
  standards have been developed in this direction
  and a list of functionality has been defined. The
  main function of mail servers is to instantly
  send information to an addressee anywhere in the
  world using special protocols, which in this
  case means the method and features of data
  transfer.
• The following mail protocols exist
• SMTP sends a letter from a computer to a mail
  server and between the same servers
• POP3 receives and forwards mail to the
  recipient in the local application (MS Outlook,
  Thunderbird)

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• IMAP also accepts, but directly in the WEB
  environment (standard interface Gmail in the
  browser).
• Regardless of what mail servers are, they all
  have several comparable characteristics
• mailbox name and domain
• gateway bandwidth and dedicated mail storage
  space
• the ability to customize the mailing list
• belonging to a particular organization.
• Modern mail servers can serve any type of domain
  and the speed of connection to the mail server
  and delivery depends on the size of the letter.
• Regardless of the type and capabilities, they all
  serve the same purpose to carry out written
  communication in the information environment
  quickly and in the most convenient way.
• Related Understanding a Web Server and Types of
  Web Servers
• What Is POP3?
• POP3 is a protocol for receiving electronic
  messages. To view mail, letters are downloaded
  to the recipients computer. After that, they can
  be deleted from the server. All actions with
  incoming mail occur on the users computer.
• This protocol has undeniable advantages

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• POP3 is an old protocol created in 1988. Its
  capabilities are no longer enough for the
  comfortable use of e-mail. It was replaced by the
  IMAP protocol.
• Differences Between POP3 and IMAP?
• IMAP (application layer protocol for accessing
  email), as well as POP3, is used to receive
  email messages to a local client, however, it has
  a significant difference only the headers of
  email messages are downloaded, the body of the
  letter itself remains on the server. This
  communication protocol works in two directions,
  if changes occur on the local client, they are
  transmitted to the server. Recently, IMAP has
  become more popular as email giants like Gmail
  recommend using it instead of POP3.
• The default IMAP ports are
• Port 143 non-encrypted port
• Port 993 SSL/TLS port, also known as IMAPS
• SMTP Mail Delivery
• In order for mail to reach its destination, the
  SMTP protocol must be able to deliver it,
  firstly, to the correct host and, secondly, to
  the correct user on this host.
• SMTP then resolves the host address using a
  domain name server (DNS) or a local host table.
  The hostname is in the users email account
  (mycompany.com) the IP address is used by SMTP
  to determine the mail server to send mail to
  (192.1.1.10).
• When the SMTP server looks up hostname addresses
  in the local hosts table, IPv6 addresses are
  ignored.
• If any of the configured DNS servers have IPv6
  addresses, then all DNS servers must support the
  recursion feature to resolve email domains for
  which those configured servers are considered
  unauthorized.

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• multiple hostnames. The SMTP server uses the
  socket interface to determine if this IP address
  belongs to the localhost.
• How SMTP Mail Is Sent?
• The email protocol performs the function of a
  relay, that is, a transmitter. Each has a unique
  address, which makes it possible to find the
  recipient when forwarding.
• The SMTP protocol accompanies the execution of
  several commands in the form of a sequence of
  requests and responses.
• The main parameters that SMTP commands send
• MAIL FROM senders address,
• RCPT TO recipient,
• DATA header and body.
• SMTP server is a kind of postman. His task is to
  pick up the package from one user, find the
  optimal and accurate way of transportation and
  give it to another user.
• Conditionally divided into
• Ordinary. For personal correspondence. More often
  they belong to providers of web hosting,
  internet networks, etc. But the peculiarity is
  that the amount of mailings is limited, usually
  for a day.
• Special repeaters. This is a server for bulk and
  transactional email campaigns. The limit ends at
  millions. You can not be afraid that the IP will
  be blocked.

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• Order on commercial service. This option is
  suitable if you plan regular mailings on a large
  scale. The use of special services increases the
  chance that letters will end up not in Spam, but
  Inbox. Most often, services offer several options
  for tariffs. To choose the best, calculate the
  approximate number of letters that you plan to
  send monthly.
• Set up in a free service. The ability to send
  letters via SMTP is provided in any modern mail
  service. Just like in the case of hosting, free
  services have limits on the number of emails
  sent. To effectively use this option, you can
  create several accounts and set up a distributed
  mailing list.
• Set up in a virtual environment. This option is
  ideal for mass mailings. At the same time, it
  has significant drawbacks. To use a virtual
  environment, it must be properly configured.
  This will require costs financial (if you
  decide to call a specialist) or time (if you
  decide to figure out the settings yourself). You
  will also need a dedicated IP address.
• Advanced SMTP Protocol
• Since its inception in 1982, the SMTP protocol
  has done an excellent job of sending messages
  between computers on the Internet. However, over
  time, the limitations laid down in the protocol
  became noticeable. Then, instead of replacing the
  standard protocol, which was widely used by that
  time, it was decided to improve some of the
  functions of the SMTP protocol. At the same time,
  a decision was made, leaving all the SMTP
  specifications in their original form, only
  adding new features to them.
• In 1995, RFC 1869 saw the light of day, which
  defined a method for extending the capabilities
  of the SMTP protocol called Extended SMTP
  Services.
• Extended SMTP (Extended SMTP) is implemented as
  follows. At the beginning of an SMTP session,
  the HELO command is replaced by the invitation
  command, EHLO. The receipt by the SMTP server of
  such a command means that the client can send
  extended SMTP commands to it.
• The TURN command has already been mentioned
  before. This command is quite effective, but
  unfortunately not safe. To compensate for this
  shortcoming, RFC 1985 defines a new
  implementation of the TURN command that provides
  greater security. The ETRN command allows an
  SMTP client to issue a request to an SMTP server
  in order to initiate another SMTP connection
  with the client in order to send messages to it.
  The only difference between ETRN and TURN is that
  the request is not to use an existing
  connection, but to open a new SMTP session. Thus,
  the SMTP server can connect to the client
  computer using the normal DNS name resolution
  algorithms. In this case, the opening of a new
  connection is not based on the name under which
  the client

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computer is registered on the server, but on the
real hostname of the client. In this case, if a
hacker establishes an unauthorized SMTP
connection and uses the ETRN command, the SMTP
server will simply establish a new connection
with the real client and forward the email to
him. As a result, there were no casualties. The
format of the ETRN command is as follows 1.
ETRN name Here, the role of the name can be
either a hostname or a domain name (if a request
is received to receive mail for the entire
domain). The ETRN team is a very good help for
the email administrator. If the mail for your
mail server is stored by the Internet provider,
then using this command you can notify him that
he is ready to receive mail collected for you.
There are several ways to implement such an
algorithm. One is to use the special Perl
program that comes with the Sendmail program. Its
job is precisely that after establishing a
connection with the ISP, it issues the ETRN
command with your domain name as an argument.
Upon receiving this command, the ISPs SMTP
server initiates another SMTP connection to your
local SMTP server (over the same PPP connection)
and delivers all the mail destined for your
domain that it has in its queue for
sending. Which Companies Need a Mail
Server? Having an idea of what a mail server is
and what it is for, you can already conclude
whether your company needs it. First of all, it
is important to determine what role mail plays
in your workflows, estimate the expected load on
the mail, as well as how much money and time you
can spend on the project. It is worth paying
attention to the number of employees of the
company. For example, for a small team of 10-20
people, we recommend creating mail on a domain,
and placing it on the servers of mail service or
hosting. Why not standard mail? Because an email
address with a unique domain has a positive
effect on the reputation of the company, is more
trustworthy and easier to remember. It also
allows the manager to keep the work of
departments under control. Among the types of
corporate mail, the mail server is more suitable
for medium and large organizations. To succeed
in this task, you will need a team of
professionals.How to hire world-class engineers
isnt a hard question anymore due to the online
engineering marketplaces. But anyway you have to
understand that even the highestsoftware
developer salary could be the cheapest
investment in your business. And this investment
will be one of the most significant.
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