ITECH1002 Network Operating System-Hexadecimal System

Virtualization - concept of creating a simulation of system resources to maximize computer resources.

Number system - formats used by a computer in working with various digits including the binary, octal and hexadecimal systems.

IP Addressing – the mechanism of assigning a unique number to every device in a network.

Virtual Box allows users to install the drivers for guest operating systems manually

Binary - Divide (1177) by 2 and take note of the remainders (0 or 1) which form the binary representation as 10010011001           2)1177 Remainder 1

            2)588 Remainder 0

            2)294 Remainder 0

            2)147 Remainder 1

            2)73 Remainder 1

            2)36 Remainder 0

            2)18 Remainder 0

            2)9 Remainder 1

            2)4 Remainder 0

            2)2 Remainder 0

              1

Octal - count every 3 digits starting from right    10, 010, 011, 001 and then convert the 3 digits to decimal to get 2231

Hexadecimal – count every 4 digits from the right 100, 1001, 1001 to get 0x499

Octal number – 1111 (decimal equivalent is 17)

Binary number – 1111(decimal equivalent is 15)

Hexadecimal number - 1111(decimal equivalent is 16)

The reason why there are less class C networks is because the host portion of the address only contains 8 bits compared to class B which contains 16 bits. With 16 bits for host portion in class B it is therefore possible to create many addresses.

An Internet Protocol (IP) – a unique number assigned to network devices to enable communication with other devices.

A subnet mask - address to identify the part of an address representing either a host or network portion.

A default gateway - interface that connects a local network to the Internet.

A DHCP servers automatically provides IP addresses to every device that connects to a network.

A DNS server translates IP addresses to Internet domain names. Client computers rely on DNS to be able to use the Internet.

IPV6 Tunnels are used to relay IP packets over protocols that are different from them. The difference in them lies in the determination of source and destination routes.

On home networks, NAT links the private IP addresses to a sole public address.

A Domain Name server (DNS) maps host names to IP addresses for connection purposes therefore doing away with the need to know IP addresses (Lammle, 2013). DNS Servers receive requests from users to resolve host names enabling them to use domain names instead of IP addresses.

teredo IPv6 address -  2001 = 0010 0000 0000 0001

6to4 IPv6 address - 2002 = 0010 0000 0000 0010

Link local address - FE80 to binary = 1111 1110 1000 0000

The Network Interface Card (NIC) uses the computer’s IP address to determine whether given computers are on the same network. The IP address has two portions, network portion and host portion. By checking the network portion, the NIC is able to determine if two computers are on the same network is they have the same network address, if they have different network portions, then they are on separate networks.

The NIC queries for the computer’s IP address with its MAC address. When it receives the correct IP address, it checks whether the address is in the same network. If on different networks, it creates a packet with a destination address and forward it to the network gateway

ifconfig - is used for configuring network interfaces (Haas, 2016)

route - used to display IP routing table and to format static paths to particular devices or computer networks (Ganapathy, 2012)

cat /etc/resolv.conf -  lists name servers that a particular  server uses when converting a host  domain name

Topic 3: Introducing Linux 

$ cp test1.file /home/Ubuntu

$ cp test1.file /root/mnt/ newtest1.file

$ cp /root/mnt/newtest1.file

rwxr-xrwx – chmod 7417  /home/ubuntu/test2

rw-r-xrwx- chmod 6417 /home/ubuntu/test2

r-xrwx-wx - chmod 4173 /home/ubuntu/test2

ls command – is used to list  files and directories contents

The syntax for using the ls command is $ ls (options) (file or directory). One of the commands that can be used with ls include [ls – a] which lists all the files as well as hidden files that are starting with “.”

pwd (print working directory) command - prints the  presently active user  directory with a complete path starting from the root. One of the options used with the pwd command is pwd version that is used to print information of the current working version.

mv command – the move  command is used to move directories and files. The syntax for using the mv command is [mv (options) source destination]. One of the options used with the mv command is [mv –u] which is stands for update and is used to update a file when source is newer than destination.

rm command – the rm(remove) command is used to delete files and directories. The syntax for using the command is [rm (option) filename]. One of the options used with remove command is [–i] which should prompt the user before file or directory removal.

The mount command is used for making file systems accessible to users   on   machines. The command makes directories, files devices available to the user as soon as the mount command is activated. The mount command initiates the OS that a given file system is ready for use and links it with its mounting point and configures selections for its access. To disconnect files from user access, the unmount command is used.

An absolute path refers to the location of a file or directory from its root directory (/). A relative path on the other hand is involves a path related to a current working directory (Surendra, 2012). An absolute path starts with a root directory for example, /home/documents. Relative paths starts in the current working directories .if a current working directory is /home/documents then /home/documents/ files represents a relative path name with the name files. If the name of presently active directory is changed, the relative path has to change too.

Wildcards are advantageous in several ways in a Linux system. Linux commands can use wildcards to accomplish actions on over one file simultaneously or they can be used to find portion of an expression in a file. For example, to create a file called home with wildcard, you would do the following [touch 'home *'].

Regular expressions are a kind of a pattern used when operating with text files and are used for manipulating several parts of a text file especially with programming languages while . and .. notation can be used to implement associative arrays.

ifconfig - is used for configuring network interfaces including  Ethernet, modem wireless, 

ifconfig | grep eth0 –A 1 -  displays the IP address used with Ethernet and removes the formerly scripts from printing the–A1 

ifconfig | grep eth0 –A 1 | grep Mask – displays the mask that was used in the address configuration

ifconfig | grep eth0 –A 1 | grep Mask | awk –F " " '{print $2}' prints out the IP address used in the configuration

T5.2

ps – A | grep gnome is used to provide information about an active process. The command will display process with gnome specifications

T5.3

touch file1 | chmod 5555 file1 – creates a new file called file1 uses the chmod command to change the mode

chmod u-x,o-x file1 – change the file1(plain file) access mode from owner(u) to others (o)

chmod u-s,g+s file1 – change file1 access mode from owner (u) to be accessible to a group(g)

References

Ganapathy, L. (2012). 7 Linux Route Command Examples (How to Add Route in Linux). Retrieved from https://www.thegeekstuff.com/2012/04/route-examples/

Haas, J. (2016). Learn  the Linux Command – ifconfig. Retrieved from https://www.lifewire.com/linux-command-ifconfig-4091934 

Lammle, T. (2013) Cisco Certified Entry Networking (CCENT) Technician, Study Guide, Second Edition

Surendra, A. (2012).  ABSOLUTE PATH VS RELATIVE PATH IN LINUX/UNIX. Retrieved from https://www.linuxnix.com/abslute-path-vs-relative-path-in-linuxunix/