Network routing is the process of determining the best path for data packets to travel from one device to another on a computer network. Routers, the backbone of network infrastructure, are responsible for facilitating this process. When a user sends data to another user or server, the router analyzes the packet's destination address and decides which path to take to reach its destination.
The Role of Routers
Routers act as traffic controllers in a network, directing data packets efficiently to their intended destinations. They maintain routing tables that contain information about various network paths, enabling them to make intelligent decisions about packet forwarding.
How Data Packets Travel
When a data packet is sent from a source device, the router examines the packet's destination IP address. The router consults its routing table to determine the best path for the packet. It then forwards the packet to the next hop, which is another router along the chosen path. This process continues until the packet reaches its final destination.
Types of Network Routing
Network routing can be classified into three main types: static routing, dynamic routing, and default routing.
Static Routing
In static routing, network administrators manually configure the routing tables in routers. This approach is suitable for smaller networks with stable topologies, where the paths between devices remain constant.
Dynamic Routing
Dynamic routing, on the other hand, uses routing protocols to automate the process of updating routing tables. Routers exchange information about the network's status and adapt to changes in real-time, making dynamic routing ideal for larger, more complex networks.
Default Routing
Default routing comes into play when a router does not have a specific entry for the destination IP address in its routing table. In such cases, the router forwards the packet to a pre-defined default gateway, which acts as a central exit point for the network
The Process of Network Routing
The process of network routing is a crucial mechanism that enables data packets to traverse efficiently through a complex web of interconnected devices on a computer network. we will delve deeper into the various steps involved in network routing, shedding light on how routers make intelligent decisions to ensure successful data transmission.
Source and Destination
At the heart of network routing is the concept of source and destination. When a user initiates data transmission, acting as the source, they specify the destination device or server where the data should ultimately arrive. This information is essential as it forms the basis for the routing process.
Building Routing Tables
One of the fundamental tasks of routers is building and maintaining routing tables. These tables contain critical information about various destinations within the network and the paths that can be taken to reach them. In dynamic routing environments, routing tables are continually updated as routers exchange information with each other, adapting to changes in the network's topology.
Determining the Best Path
Once a router receives a data packet from the source, it examines the destination address of the packet. Using the information stored in its routing table, the router evaluates various available paths to determine the best route for the data packet to take. This decision-making process involves considering metrics such as link cost, which assesses the efficiency and reliability of potential paths.
Forwarding Data Packets
With the best path identified, the router proceeds to forward the data packet to the next hop. The next hop refers to the next router along the chosen path that brings the data packet closer to its final destination. This forwarding process occurs iteratively at each router until the data packet reaches its intended endpoint.
In this Articles we are going to look into steps on how to configure network routing.
To ensure the firewall policies are enforced, outbound application traffic must be routed through the firewall. To do that:
- A route table is required. This route table will be associated with the frontend and backend subnets.
- A route is required to filter all outbound IP traffic from the subnets to the firewall. The firewall’s private IP address will be used.
To configure network routing, we going to perform the following tasks:
- Create and configure a route table.
- Link a route table to a subnet.
Create a route table
Azure automatically creates a route table for each subnet within an Azure virtual network. The route table includes the default system routes. You can create route tables and routes to override Azure’s default system routes.
Record the private IP address of app-vnet-firewall
1.In the search box at the top of the portal, enter Firewall. Select Firewall in the search results
2.Select app-vnet-firewall
3.Select Overview and record the Private IP address
Add the route table
1.In the search box, enter Route tables. When Route table appears in the search results, select it.
2.In the Route table page, select + Create
3.Create the route table
- Subscription Select your subscription
- Resource group RG1
- Region East US
- Name app-vnet-firewall-rt
4.Select Review + create
5.After validation pass. Select Create
6.Wait for the route table to deploy, then select Go to resource
Associate the route table to the subnets
1.In the portal, continue working with the route table, select app-vnet-firewall-rt
2.In the Settings blade, select Subnets and then + Associate
3.Configure an association to the frontend subnet, then select OK.
4.Configure an association to the backend subnet, then select OK
Create a route in the route table
1.In the portal, continue working with the route table, select app-vnet-firewall-rt
2.In the Settings blade, select Routes and then + Add.
3.Configure the route, then select Add.
- Route name ** outbound-firewall**
- Destination type IP addresses
- Destination IP addresses/CIDR range 0.0.0.0/0
- Next hop type Virtual appliance
- Next hop address private IP address of the firewall
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