●Other protocols used for e-mail
Other protocols that extend the data formats or provide added security
functions are summarized below.
Protocol
MIME
S/MIME
APOP
Description
A protocol that extends the data formats for sending and receiving
e-mail, in addition to the text format. Using MIME, it is possible to send
and receive multimedia files such as static images, video, and audio
media as attachments.
A protocol that extends MIME with additional security functions (encryption functions). Can be used to prevent interception, spoofing, and
falsification of e-mail.
Protocol that encrypts passwords. Can be used to encrypt passwords
sent to providers when retrieving e-mail.
Reference
MIME
Abbreviation for “Multipurpose Internet
Mail Extensions.”
Reference
S/MIME
Abbreviation for “Secure/Multipurpose
Internet Mail Extensions.”
Reference
APOP
Abbreviation for “Authenticated Post Office Protocol.”
Chapter 9
9-4-3 Network application
1
Framework of the Internet
The Internet was born when the “ARPANET ( Advanced Research
Projects Agency Network)” was created as a distributed computer network by the United States Department of Defense in 1969. In the early
1970s, research institutes such as those at universities were connected to
the network, and in 1991 the network was opened to commercial providers. The Internet has since spread at an explosive rate to become what it is
today.
Computers from around the globe can mutually connect over the Internet
through the use of protocols to exchange information.
(1)DNS
“DNS (Domain Name System)” is a framework for providing services to
manage the one-to-one matching of IP addresses and domain names. When
computers communicate to each other, IP addresses are used to find the
other computer. However, since IP addresses are represented as numbers,
they are difficult for people to use. A domain name is therefore used as a
separate name for an IP address.
Reference
ARPANET
Abbreviation for “Advanced Research
Projects Agency NETwork.”
Technology element
There are many kinds of services that can be used over the Internet. In order to utilize these services, it is necessary to understand the framework of
the Internet.
Reference
DNS
Abbreviation for “Domain Name System.”
(2)Domain name
A “domain name” uses a combination of characters to represent an IP address, and is easier for people to understand. Domain names are generally
used to access servers over the Internet.
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