Internet Protocols.

TCP - Transmission Control Protocol
TCP is used for transmission of data
from an application to the network.
TCP is responsible for breaking data
down into IP packets before they
are sent, and for assembling the
packets when they arrive.

IP - Internet Protocol
IP takes care of the communication
with other computers.
IP is responsible for the sending
and receiving data packets over the
Internet.

HTTP - Hyper Text Transfer Protocol
HTTP takes care of the
communication between a web
server and a web browser.
HTTP is used for sending requests
from a web client (a browser) to a
web server, returning web content
(web pages) from the server back to
the client.

HTTPS - Secure HTTP
HTTPS takes care of secure
communication between a web
server and a web browser.
HTTPS typically handles credit card
transactions and other sensitive
data.

SSL - Secure Sockets Layer
The SSL protocol is used for
encryption of data for secure data
transmission.

SMTP - Simple Mail Transfer
Protocol
SMTP is used for transmission of e-
mails.

MIME - Multi-purpose Internet Mail
Extensions
The MIME protocol lets SMTP
transmit multimedia files including
voice, audio, and binary data across
TCP/IP networks.

IMAP - Internet Message Access
Protocol
IMAP is used for storing and
retrieving e-mails.

POP - Post Office Protocol
POP is used for downloading e-
mails from an e-mail server to a
personal computer.

FTP - File Transfer Protocol
FTP takes care of transmission of
files between computers.

NTP - Network Time Protocol
NTP is used to synchronize the time
(the clock) between computers.

DHCP - Dynamic Host Configuration
Protocol
DHCP is used for allocation of
dynamic IP addresses to computers
in a network.

SNMP - Simple Network
Management Protocol
SNMP is used for administration of
computer networks.

LDAP - Lightweight Directory Access
Protocol
LDAP is used for collecting
information about users and e-mail
addresses from the internet.

ICMP - Internet Control Message
Protocol
ICMP takes care of error-handling in
the network.

ARP - Address Resolution Protocol
ARP is used by IP to find the
hardware address of a computer
network card based on the IP
address.

RARP - Reverse Address Resolution
Protocol
RARP is used by IP to find the IP
address based on the hardware
address of a computer network
card.

BOOTP - Boot Protocol
BOOTP is used for booting (starting)
computers from the network.

PPTP - Point to Point Tunneling
Protocol
PPTP is used for setting up a
connection (tunnel) between private
networks.
When you write an email, you don't
use TCP/IP.
When you write an email, you use
an email program like Lotus Notes,
Microsoft Outlook or Netscape
Communicator.
Your Email Program Does
Your email program uses different
TCP/IP protocols:
It sends your emails using SMTP
It can download your emails from
an email server using POP
It can connect to an email server
using IMAP

SMTP - Simple Mail Transfer
Protocol
The SMTP protocol is used for the
transmission of e-mails. SMTP takes
care of sending your email to
another computer.
Normally your email is sent to an
email server (SMTP server), and then
to another server or servers, and
finally to its destination.
SMTP can only transmit pure text. It
cannot transmit binary data like
pictures, sounds or movies.
SMTP uses the MIME protocol to
send binary data across TCP/IP
networks. The MIME protocol
converts binary data to pure text.
POP - Post Office Protocol
The POP protocol is used by email
programs (like Microsoft Outlook) to
retrieve emails from an email
server.
If your email program uses POP, all
your emails are downloaded to your
email program (also called email
client), each time it connects to
your email server.
IMAP - Internet Message Access
Protocol
The IMAP protocol is used by email
programs (like Microsoft Outlook)
just like the POP protocol.
The main difference between the
IMAP protocol and the POP
protocol is that the IMAP protocol
will not automatically download all
your emails each time your email
program connects to your email
server.
The IMAP protocol allows you to
look through your email messages at
the email server before you
download them. With IMAP you can
choose to download your messages
or just delete them. This way IMAP
is perfect if you need to connect to
your email server from different
locations, but only want to
download your messages when you
are back in your office.