Azure Front Door is a global network service provided by Microsoft Azure that optimizes content delivery and improves web application performance. Designed to ensure high availability, the service also offers advanced security features, such as DDoS protection and web application firewall, thus supporting companies in maintaining high performance and security for their globally distributed applications. In this article, we'll learn more about what Azure Front Door is, what are its main characteristics, the differences with other Azure balancing and load distribution services, and what are the factors that influence the cost of the service.
Azure Front Door is a Content Delivery Network (CDN) service with global load balancer functions that provides DDoS protection, caching and web application firewall (WAF) capabilities. It is a highly available and scalable platform designed for web applications, cloud services and virtual machines.
It is a cloud-based service that serves to distribute and cache content (to facilitate its distribution), whether they are web apps or websites, and that accelerates their performance by dynamically distributing traffic over the fastest and most available routes, acting as a scalable and secure entry point, managing and filtering traffic at the edge of Microsoft's global network.
The service is designed to handle high loads and complex environments, making it an ideal choice for businesses looking to optimize the reliability and user experience of their applications.
The underlying Azure Front Door technology has made it easy to scale and secure many popular Microsoft services, including Office 365, Xbox, LinkedIn, Bing, and Teams, and can help transform business applications into robust and customized modern applications. Let's see how in the next sections.
Before we start talking in more detail about Front Door, let's try to understand a moment better what a CDN is.
Simply put, it's just a distributed network of servers that can efficiently deliver web content to users. A Content Delivery Network caches content on peripheral servers at points of presence (POPs) located close to end users, to minimize latency.
Azure Front Door does exactly this and, in addition to its CDN functions, it also offers a suite of load balancing solutions for applications and is positioned at the beginning of its digital infrastructure as the first point of contact for users looking for our applications.
The service works at level 7 (Application) of the OSI Model (Open Systems Interconnection, a theoretical structure that describes how data is transmitted through a communication network) and uses the protocol Anycast, a routing technique in computer networks that allows multiple servers to share the same IP address.
When a data packet is sent to this anycast address, the network router routes the packet to the nearest server or node with the best connection, depending on network metrics.
To manage requests, anycast uses two rings of nodes based on the user's position: the inner ring is the preferred one for managing the request, while the outer ring takes over in case of network problems or excessive requests. This method improves load distribution, reduces latency, and increases reliability, since traffic can be managed by servers that are geographically close to the end user or that offer the best performance.
The main task of the service is therefore, in short, to serve content in a fast, secure, and reliable way, whether static or dynamic and, if these contents are not already available in the cache, route client requests to the backend of the application (which can be any internet service hosted inside or outside Azure) which at that time turns out to be faster and more available, optimizing user access to web applications, APIs and contents, improving reliability and, with its dedicated functionality, security.
Your website's DNS is pointed to the Azure Front Door endpoint (a logical set of one or more routes associated with domain names) using a CName record and a TXT record. The CName record is used to direct traffic to the Front Door endpoint address, while the TXT record confirms domain ownership. The domain name is associated with the created endpoint (within a profile on Front Door) through the cname record, so that traffic is diverted to Front Door, instead of to the servers, which will then be contacted by the latter who will act as an intermediary between the two.
Once a user is directed to Front Door, the Front Door instance checks the health of its application servers, the validity of the cached content, and ensures that the request is not an attack. If everything is in order (and if the contents are not already available in the cache), the service will direct the user to the relevant content or application servers (or to the origin). If an application server or region isn't available, Front Door can redirect the request to an alternative healthy endpoint or even a custom error page.
Its design focuses on three fundamental aspects for this type of application:
Let's now explore the details of the features offered by Azure Front Door:
The security aspect is one of the fundamental elements that has greatly influenced the decision of many companies to implement Azure Front Door for their projects. In fact, compared to other load balancers, this service provides an additional layer of protection, acting as a single point of access to our web applications. By properly configuring Front Door, you can take advantage of various security measures, including:
We have created the Infrastructure & Security team, focused on the Azure cloud, to better respond to the needs of our customers who involve us in technical and strategic decisions. In addition to configuring and managing the tenant, we also take care of:
With Dev4Side, you have a reliable partner that supports you across the entire Microsoft application ecosystem.
CDNs and load balancers are nothing new in the IT world; however, the Azure platform has evolved over the years to offer different solutions dedicated to content distribution and load balancing such as Azure Application Gateway, Azure Front Door and Azure Traffic Manager so that you can choose the most suitable solution based on the requirements of your projects.
When selecting the right solution, there are many factors to consider. Below are the key decisions that Microsoft has specified to support this choice.
In the next sections, we will explore the differences between Front Door and the other two services mentioned above to understand what is the right choice to make for your needs.
Azure Front Door and Azure Application Gateway are similar services that offer load balancing and traffic management capabilities. Although both offer layer 7 load balancer functions (HTTP/HTTPS), the main difference is that Front Door is predominantly a CDN platform with a global reach, while Application Gateway is a regional service, focused primarily on application-level routing and load balancing within a specific region or virtual network.
Although the differences between the two (in particular with regard to load balancing functions) may appear trivial on the surface, they are not trivial at all and can cause serious variations in terms of the architecture of the solutions adopted and, above all, of costs.
In fact, Front Door is incredibly more cost-efficient than Application Gateway because its implementation requires the deployment of a smaller number of instances and has much faster failover times (a security mechanism used in computer systems to ensure service continuity) than Application Gateway by virtue of its much more direct approach to traffic management.
In addition, with Front Door it is not necessary to manage authentication certificates manually and the service automatically takes care of the provision and renewal of certificates well before their expiration, thus reducing the risk of service interruptions due to expired certificates, without additional costs for acquiring or renewing certificates.
The downside for Front Door is the lack of some features that AG has, such as Mutual Authentication (which requires both the client and the server to authenticate each other during a TLS connection, ensuring an additional level of security where both parties must present valid certificates before establishing communication) and Connection Draining (which allows active connections to be completed on an instance of the backend server before removing it from the service, ensuring an uninterrupted disconnect for users).
Although it is possible to use both Azure Application Gateway and Azure Front Door together, placing Application Gateway behind Front Door, these cases are not common. In most typical cases, each service can independently fulfill the required functionality.
However, there may be situations where you need some unique features, such as Managed Certificates, Connection Draining, or faster Failovers, which are available in one service but not in the other. In such cases, the combined use of Azure Application Gateway and Azure Front Door becomes necessary to obtain the desired functionality.
Azure Traffic Manager acts as a layer 4 (Transport) load balancing solution in the OSI model and based on DNS (Domain Name System, a system that translates human-readable domain names into numerical IP addresses that computers use to identify and communicate with each other on a network).
It acts as an intermediary between the DNS of your custom domain and multiple public endpoints, allowing you to direct traffic to these endpoints using different routing methods. Available DNS routing methods include performance-based, weighted, prioritized, geographic, and subnet-based routing. In addition, Traffic Manager monitors the health of each endpoint, which can be a service hosted on Azure accessible via the internet or outside the Azure environment.
The central difference that should immediately catch the eye is that of the layer in the OSI model. Front Door is in fact a level 7 solution (Application), where Traffic Manager is instead level 4.
But what does it mean in a nutshell? L4 load balancers, operating at the transport layer, are able to handle L4 protocols such as TCP and UDP. L7, being the application layer, focuses on protocols built on top of these protocols (for example: HTTP, SMTP). Because they operate at the application level, L7 load balancers can also handle more “sophisticated” operations such as security, routing, performance, and so on.
If it's still not clear, let's make it even easier with an example. Let's imagine we have a website or application that needs to be globally accessible. Traffic Manager is like a 'traffic controller' that decides which server should respond to a request. It does not directly manage traffic, but it directs users to the most suitable server based on rules such as geographical proximity, performance and priority of the server.
Azure Front Door, on the other hand, is more like a 'doorman' that not only directs users to the right server, but also ensures that they have a fast and risk-free service as possible. Its position within the infrastructure is “in front” of the servers and it can manage global traffic and send it to the right server, such as Traffic Manager, but with more advanced functionality. It also offers a cache to make pages load faster and provides greater security features against attacks (such as DDoS) and checks that traffic is secure.
The Azure Front Door pricing model is designed to meet the different needs and scales of organizations. It includes multiple billing components, including data transfer costs, the number of HTTP (S) requests, and any additional functionality such as WAF and custom domain hosting. The pricing structure of Azure Front Door is designed to ensure that organizations pay only for what they use, making it affordable for both small startups and large enterprises.
Starting at the base, each Front Door profile involves an hourly rate and a fee is charged for each hour, or fraction of an hour, that the profile is distributed. The rate applied depends on the tier selected. A single Front Door profile can contain multiple endpoints and there is no additional charge for each endpoint.
Organizations considering Azure Front Door can choose between Standard and Premium pricing levels, each offering a different set of features and capabilities adapted to various use cases. The Azure Front Door Standard tier focuses on providing basic CDN, WAF and global load balancing services, suitable for businesses looking to improve the performance and security of their web applications. On the other hand, Azure Front Door Premium includes advanced security features, including Microsoft Threat Intelligence for enhanced protection against sophisticated threats, making it ideal for businesses with stringent security requirements.
It should be noted that you don't pay additional costs to use features such as traffic acceleration, response caching, response compression, the rule engine, Front Door DDoS protection and custom web application firewall (WAF) rules, and if you use Front Door Premium, there are no additional costs even to use WAF managed rule sets or Private Links.
Effectively managing costs while optimizing the resources used by Azure Front Door is crucial for businesses that aim to maintain cost efficiency without compromising performance and security. By closely monitoring usage patterns and adopting best practices such as content compression, strategic cache usage, and reducing the number of HTTP (S) requests, organizations can significantly reduce their Front Door costs.
In addition, taking advantage of Azure Cost Management tools provides companies with detailed information on the use of Azure Front Door, allowing them to identify and eliminate any inefficiencies.
Another strategy for managing costs is to optimize routing rules and WAF policies to ensure that resources are used as efficiently as possible. By optimizing these configurations, companies can prevent the over-utilization of backend resources and mitigate potential security threats more effectively, thus avoiding unnecessary expenses.
In addition, subscribing to the Azure Front Door Premium tier and taking advantage of its advanced features can lead to long-term savings by improving security posture and application performance, thus reducing the need for separate security solutions and performance improvement tools.
But where to start, then, to explore prices in greater depth? Organizations can take advantage of tools such as the Azure Cost Calculator (available hither), which includes options specific to Azure Front Door, to create accurate cost projections based on their unique needs.
By entering details such as expected data transfer volumes, the number of HTTP (S) requests, and any additional functionality required (WAF, custom domains), businesses can obtain a detailed cost estimate that helps in planning the budget for the Front Door deployment.
Whatever the purpose of your HTTP (S) application, it's important that your customers are always protected, served quickly and consistently, and want to use the service again.
Azure Front Door can help organizations of all types and sizes achieve these goals by offering industry-leading WAF protection, acceleration of CDN requests, and global availability and scalability, to ensure that customers always leave the application satisfied with the user experience.
The service is designed to serve content, with its features dedicated to caching to improve response times on static content, dynamic site acceleration for dynamic content, route configuration and various security settings for their web applications, it stands out as a complete solution for companies that aim to improve their online presence. With Microsoft's quick guides, you can easily configure a test instance of Front Door, so why not try it and find out if it's the right tool for your needs as well.
Azure Front Door is a Content Delivery Network (CDN) service with global load balancing. It is designed to improve the performance, availability, and security of web applications, offering features such as DDoS protection, advanced caching, Web Application Firewall (WAF), and intelligent traffic routing.
Azure Front Door isn't just a CDN, but it includes advanced traffic balancing and security features. Unlike a traditional CDN, it manages intelligent request routing and protects applications with advanced security tools, such as WAF and DDoS mitigation.
Azure Front Door offers intelligent routing to direct traffic to the nearest and fastest endpoint. It includes global load balancing, caching and content optimization to reduce latency, DDoS protection, Web Application Firewall, and SSL/TLS support for secure end-to-end connections.
Azure Front Door is a global service, designed to distribute traffic across multiple regions and is optimized for application-level load balancing on a global scale. Azure Application Gateway, on the other hand, is a regional service, focused on managing traffic within a specific virtual network, with advanced security and connection management features.
Azure Traffic Manager operates at DNS level (level 4 of the OSI model) and directs traffic to the nearest endpoints, without directly managing requests. Azure Front Door operates at level 7 (Application) and offers more advanced control, with caching, security and intelligent traffic routing functions.
To configure a custom domain, you must create an endpoint in Azure Front Door, add the custom domain, verify ownership through a CNAME record and a TXT record in the DNS, and configure SSL/TLS certificates, which are automatically managed by Front Door.
Azure Front Door offers two price levels: Standard, which includes basic functionality such as CDN, WAF, and global load balancing, and Premium, which adds advanced security and threat protection capabilities. The costs depend on the data traffic transferred, the number of HTTP/S requests and the security features activated.
To reduce costs, it is recommended to use caching to limit the number of requests to backends, enable content compression, monitor usage with Azure Cost Management, optimize routing rules and avoid unnecessary HTTP/S requests. Choosing the level of service that best suits your needs helps you balance cost and functionality.
No, Azure Front Door can also balance traffic to backends outside Azure, including on-premises servers or third-party clouds.
Yes, Azure Front Door can be combined with Azure Application Gateway to manage local traffic and with Azure Traffic Manager for DNS-based failover, creating a more resilient architecture.
Azure Front Door is ideal for companies that have globally distributed web applications and want to reduce latency, improve security with DDoS and WAF protection, and optimize performance with advanced caching. It is particularly suitable for e-commerce, finance and sectors with high security requirements.
Yes, Azure Front Door includes native DDoS protection and works in combination with Azure DDoS Protection to detect and mitigate volumetric and application attacks.
The Infra & Security team focuses on the management and evolution of our customers' Microsoft Azure tenants. Besides configuring and managing these tenants, the team is responsible for creating application deployments through DevOps pipelines. It also monitors and manages all security aspects of the tenants and supports Security Operations Centers (SOC).
