TCP / IP

• TCP / IP (Transmission Control Protocol / Internet Protocol)
• Communication protocol for the internet

IP address

• A series of 4 numbers between 0 and 255 (32 bits total) for addressing a computer (i.e. 192.168.1.100)

Domain names

• Names used for IP addresses (i.e. http://www.domain.com)
• Domain names are translated to an IP address by a DNS process (Domain Name Server)
• DNS servers update each other about new domain names and IP addresses
• DNS changes typically take 24 - 36 hours to permeate the internet

Primary protocols

TCP

• Transmission Control Protocol
• Communication between applications (via the network) (application -> network, network -> application)
• Fixed connection
• Full-duplex communication
• Occupies the communication line between the two computers

• Breaks data down into IP packets, and reassembles them when they arrive at the destination computer

IP

• Internet Protocol
• Communication between computers
• Connection-less communication protocol
• Does not occupy the communication line between the two computers

• Routes packets of data to the destination computer
• Each IP packet must have an IP address (for the destination computer)

Additional protocols

ARP

• Address Resolution Protocol
• Used by the IP protocol to find the hardware address of a computer network card based on the IP address

BOOTP

• Boot Protocol
• Booting computers from the network

DHCP

• Dynamic Host Configuration Protocol
• Allocation of dynamic IP addresses to computers in a network

FTP

• File Transfer Protocol
• Transmission of files between computers

HTTP

• HyperText Transfer Protocol
• Communication between a web server and a web browser
• Used for sending requests from a web client (a browser) to a web server and sending web content (web pages) from the server back to the client

HTTPS

• Secure HTTP
• Secure communication between a web server and a web browser
• Useful for credit card transactions and other sensitive data

ICMP

• Internet Control Message Protocol
• Errors and statistics for the network

IMAP

• Internet Message Access Protocol
• Storing and retrieving emails
• Connecting to an email server from a personal computer

LDAP

• Lightweight Directory Access Protocol
• Collecting information about users and e-mail addresses from the Internet

NTP

• Network Time Protocol
• Synchronizing the time for different computers

POP

• Post Office Protocol
• Receiving emails
• Downloading emails from an email server to a personal computer

PPTP

• Point to Point Tunneling Protocol
• Setting up a connection (tunnel) between private networks

RARP

• Reverse Address Resolution Protocol
• Used by the IP protocol to find the IP address of a computer network card based on the hardware address

SMTP

• Simple Mail Transfer Protocol
• Sending emails
• Uploading emails from a personal computer to an email server
• Can only transmit plain text (binary data must be encoded before it's sent)

SNMP

• Simple Network Management Protocol
• Administration of computer networks

SSL

• Secure Sockets Layer
• Encryption of data for secure data transmission

UDP

• User Datagram Protocol
• Simple communication between applications (via the network) (application -> network, network -> application)