Chapter 6.5 IP Networking

172.16.1.26 2.2.2.2 A valid IPv4 address consists of 4 8-bit (1 byte) numbers separated by periods. For example, 10.0.0.65. Because they are 8 bits long, these numbers are frequently called octets. Even though we typically express these numbers using decimal notation, it's important to remember that these numbers are binary numbers. The lowest value one of these numbers can have is 00000000. The decimal equivalent for this number is simply 0. The highest value one these numbers can take is 11111111. The decimal equivalent of this number is 255. Therefore, in decimal notation, each octet must contain a number between 0 and 255 inclusively.

192.15.5.55 223.16.5.0 222.55.0.0 The following are class C addresses: 192.15.5.55, 22.55.0.0, and 223.16.5.0. The first octet of Class C addresses is in the range of 192 to 223. The first octet of Class A addresses range from 1-126. The first octet of Class B addresses range from 128-191.

114.0.0.15 114.58.12.0 114.122.66.12 With a Class A network, the first octet indicates the network address. All hosts on the network must have the same value in the first octet (114).

129.0.0.1 191.168.2.15 168.16.5.1 IP addresses are divided into classes. The most common of these are classes A, B, and C. Each address class has a different default subnet mask. To identify the class of an IP address, look at its first octet. Class A networks use a default subnet mask of 255.0.0.0 and have 0-126 as their first octet. Class B networks use a default subnet mask of 255.255.0.0 and have 128-191 as their fist octet. Class C networks use a default subnet mask of 255.255.255.0 and have 192-223 as their fist octet. In this question, the IP address that fall in the Class B IP address range are 191.168.2.15, 129.0.0.1, and 168.16.5.1.

169.254.0.1 - 169.254.255.254 The Internet Assigned Numbers Authority (IANA) has reserved 169.254.0.1 through 169.254.255.254 for Automatic Private IP Addressing (APIPA). APIPA also sets the subnet mask on the network to 255.255.0.0.

127.0.0.1 127.0.0.1 is the loopback address for any device. This special address means "this host." If you ping the lookback address, TCP/IP configuration will be tested. A successful test means that TCP/IP is correctly configured on the host. 192.168.1.55 is the current IP address assigned to the host. You can ping this address, but the address is not considered the loopback address. Also, to tests the current host regardless of its current IP address. 192.168.1.255 is the broadcast address for the network meaning "any host" on the network.

IP The IP is the protocol of the Internet. If you want to use the Internet, your computer must have the IP protocol installed and configured. The Serial Line Internet Protocol (SLIP) is a mostly obsolete encapsulation of the Internet Protocol designed to work over serial ports and modem connections. The Point-to-Point Protocol (PPP) is also commonly used with modem connections. IPX/SPX is the protocol suite used on legacy NetWare networks. NetBIOS is the term used to describe the combination of two protocols: NetBEUI and NetBIOS. NetBIOS was used in early Windows networks. Because NetBIOS is a non-routable protocol, it was often combined with TCP/IP or IPX/SPX to enable internetwork communications.

HTTPS HTTP The HyperText Transfer Protocol (HTTP) is used by Web servers and browsers to transmit Web pages over the Internet. This is often confused with HTML or HyperText Markup Language, which is the markup language used to create Web content. XMLis also a markup language. SMTP is used to route electronic mail through the internetwork. E-mail applications provide the interface to communicate with SMTP or mail servers. The Network News Transfer Protocol or NNTP is an Internet application protocol used primarily for reading and posting Usenet articles.

FTP You should implement the File Transfer Protocol (FTP). It enables file transfers and supports user authentication. The Trivial File Transfer Protocol (TFTP) also enables file transfer, but does not support user authentication. The Simple Mail Transfer Protocol (SMTP) is used to transfer email message from email clients to email servers. The Light weight Directory Access Protocol is used to access information about network resources stored in a directory server. The Secure SHell protocol (SSH) is used to securely access the console prompt of a remote computer system. The Simple Network Management Protocol (SNMP) is used to remotely monito and manage network devices and hosts.

SMTP SMTP sens email from a mail client to a mail server. FTP provides a generic method of transferring files. SNMP is used in network management systems to monitor network-attached devices for conditions that warrant administrative attention. POP3 and IMAP are both e-mail protocols used by mail clients to retrieve e-mail from a mail server; however they can be used to send mail from the client to the server. The Trivial File Transfer Protocol (TFTP) is used for network file transfers.

DNS You can use DNS name resolution for Linux workstations (as well as for most other operating systems). NetBIOS name resolution (LMHOSTS files or WINS) is typically used on Windows-based networks. The Lmhosts file is a local text file that maps Internet Protocol (IP) addresses to NetBIOS names of remote servers with which you want to communicate over the TCP/IP protocol. A WINS server address is only needed if you have older Windows clients on multiple networks. Network Time Protocol (NTP) is a means of transmitting time signals over a computer network. Simple Mail Transfer Protocol (SMTP) is used to route electronic mail through the internetwork. E-mail applications provide the interface to communicate with SMTP or mail servers.

HTTP HTTP is used by Web browsers and Web servers to exchange files (such as Web pages) though the network. HTML is a data format that is used to create hypertext documents that can be viewed from multiple platforms. SSL secures messages being transmitted on the netwrok. SMTP is used to route electronics mail through an internetwork.

POP3 The POP3 protocol is part of the IP protocol suite and used to retrieve e-mail from a remote server to a local client over a network connection. SNMP is a protocol used to monitor network traffic. SMTP is an IP protocol used to send e-mail. FTP is used to transfer files.

53 The DNS service runs on port 53 by default. Port 110 is used by the POP3 protocol. Port 143 is used by the IMAP protocol. Port 123 is used by the NTP protocol.

Port 22 - Secure Shell (SSH) Port 548 - Apple Filling Protocol (AFP) Port 443 - HTTP over SSL (HTTPS) Port 80 - Hypertext Transfer Protocol (HTTP) Port 445 - Server Message Block (SMB/CIFS) directly over TCP Port 427 - Service Location Protocol (SLP) Port 143 - Internet Message Access Protocol (IMAP)