Administering Networking OS — Network Configuration #10

College Online Material

Basic Networking

Basic Networking Terminology

• Host — a host is any device that communicates with another device on a network
• Network — a network is a collection of two or more host that is able to communicate with each other
• Internet — a publically accessible network that connects millions of host throughout the world
• Wi-Fi — wireless networks
• Server/Service — when a host provides a feature to another host, that feature is called a service. For example, a web server provides the service of web pages
• Client — a client is a host that is accessing a server
• Router — also called a gateway, a router is a machine that connects hosts from one network to another network

Networking Features Terminology

• Network packet — used to send network communication between hosts
• IP address — an Internet Protocol (IP) address is a unique number assigned to hosts on a network
• Network mask — also called a netmask or mask, a network mask is a number system that can be used to define which IP addresses are considered to be within a single network
• Hostname — each host is provided a human-understandable name, called a hostname. Hostnames are translated into IP addresses before the network packet is sent on the network
• DHCP — hosts can be assigned hostnames, IP addresses, and other network-related information by a DHCP (Dynamic Host Configuration Protocol) server
• DNS — a server that provides the service of translating IP addresses to hostnames
• Ethernet — In a wired network environment, Ethernet is the most common way to physically connect the hosts into a network
• TCP/IP — The Transmission Control Protocol/Internet Protocol (TCP/IP) is a fancy name for a collection of protocols (remember, protocol = set of rules) that are used to define how network communication should take place between hosts

Configuring The Network

GUI

• Click on the system in the menu bar, then Preferences, and then network connection

• To modify this network device, click on the device name and then click the edit button

• If you click on the IPv4 settings tab, you can change key IPv4 values

• Click method to change from manual to DHCP

Configuration Files

Primary interface conf. file /etc/network/interfaces

List all network interface ip -a

IPv4 settings for static host

• ipaddr — hosts IP address
• gateway — router IP address
• dns1 — DNS server IP address

IPv4 settings for DHCP client host

• bootproto — set to DHCP

After configuration

• sudo ip a flush enp0s3
• sudo systemctl restart networking.service

Additional configuration

• hostnamectl — HOSTNAME info
• /etc/sysconfig/network — network and hostname settings
• /etc/resolv.conf — DNS server settings
• /etc/host — local hostname to IP address translation
• /etc/nsswtich.conf — used to modify which hostname to IP address translation service

Restarting The Network

$ service network restart
$ sudo systemctl restart netwroking.service

Network Utilities

Network Tools

• ifconfig — Displays interface configuration information
• route — Displays the routing table
• ping — Used to determine if a remote machine can be contacted via the network
• netstat — Display network statistics
• dig — Displays query results from DNS servers
• ssh — Allows a user to login into a remote machine