Basic Networking
The purpose of this chapter is to provide a basic understanding of the Oracle Cloud Infrastructure (OCI) Networking service. This chapter will be divided into three main sections. The first section will explain the general concepts and components of a net
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Basic Networking The purpose of this chapter is to provide a basic understanding of the Oracle Cloud Infrastructure (OCI) Networking service. This chapter will be divided into three main sections. The first section will explain the general concepts and components of a network. The second will explain the concepts and components of an Oracle Cloud Virtual Cloud Network (VCN) and how we can relate to the on-premise network. In the third section, we will conclude with an example of a network topology and the way to create this VCN using the “Networking Quickstart” wizard.
Networking Concepts A network is defined as a group of nodes (computers and devices) connecting in a way that they can communicate with each other, sending and receiving data over the network. Each node is uniquely identified across the network by its own IP address. A router is used to manage and route the traffic within a network. In order to secure the traffic, the concept of network segmentation and firewall are used. All of this will be explained in this section.
IP Address As we have mentioned, the IP address uniquely identified a node within a network. The common type of IP address is the IPv4, for example, 10.0.0.0. Each of the four numbers can range from 0 to 255. As you can imagine, IPv4 has a limit in terms of available IP addresses, considering the explosion of new devices around the world. IPv6 is another type of IP that provides a much larger number of IP addresses for the future. An IPv6 address is composed of eight groups of four hexadecimal digits; here is an example: 2002:0db7:15a3:0000:0000:8b3r:0456:1234.
© Adrian Png and Luc Demanche 2020 A. Png and L. Demanche, Getting Started with Oracle Cloud Free Tier, https://doi.org/10.1007/978-1-4842-6011-1_3
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Chapter 3
Basic Networking
Note IPv4 supports a maximum of 4.3 billion of IP addresses. IPv6, in theory, will never run out.
Router A router is used to route the data packets from a source to a destination, using route rules. Source and destination are usually other networks (on-premise or virtual networks) or gateways. Routers inspect the destination IP addresses of a network request. If it matches a route rule, it will forward the data packet to the destination. If no route rule matches the source and the destination, the packet will simply be dropped. A route rule is a destination and a target that instructs the packet where and how to transmit. For example, in Table 3-1 we have a route rule to allow the traffic to access the Internet through the Internet Gateway.
Table 3-1. Route rule Destination
Target
0.0.0.0/0
Internet Gateway vcn-20200614-0910
Note Route tables contain the route rules.
Firewall The Internet eases the day-to-day communication, but it also has security and vulnerability issues. Firewalls were introduced in order to secure the traffic between various networks and devices. A firewall examines the flow of data from the source and either permits or blocks the packet based on security rules. Firewalls shouldn’t only examine traffic from exter
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