Linux in a Nutshell, Fourth Edition

Overview of TCP/IP

TCP/IP is a set of communications protocols that define how different types of computers talk to one another. It’s named for its two most common protocols, the Transmission Control Protocol and the Internet Protocol. The Internet Protocol moves data between hosts: it splits data into packets, which are then forwarded to machines via the network. The Transmission Control Protocol ensures that the packets in a message are reassembled in the correct order at their final destination and that any missing datagrams are re-sent until they are correctly received. Other protocols provided as part of TCP/IP include:

Address Resolution Protocol (ARP)

Translates between Internet and local hardware addresses (Ethernet, etc.)

Internet Control Message Protocol (ICMP)

Error-message and control protocol

Point-to-Point Protocol (PPP)

Enables TCP/IP (and other protocols) to be carried across both synchronous and asynchronous point-to-point serial links

Reverse Address Resolution Protocol (RARP)

Translates between local hardware and Internet addresses (opposite of ARP)

Simple Mail Transport Protocol (SMTP)

Used by sendmail to send mail via TCP/IP

Simple Network Management Protocol (SNMP)

Performs distributed network management functions via TCP/IP

User Datagram Protocol (UDP)

Provides data transfer, but without the reliable delivery capabilities of TCP

TCP/IP is covered in-depth in the three-volume set Internetworking with TCP/IP (Prentice Hall). The commands in this chapter and ...