Server Types and Functions

The basic function of a server is to manage network resources accessed by network clients. The term "server" can refer both to a program that performs these operations and to a machine that runs one or more server programs. The following table lists servers by class (or purpose). LAN administrators can mix and match server functions without regard to their class, but it's helpful to see the role the servers play relative to Web, firewall, email, DNS, or LAN duties.
When allocating servers for website deployment, several factors must be taken into consideration to ensure optimal performance, scalability, reliability, and security. Here are the key considerations:

1. Website Traffic and Performance Requirements
   • Expected Traffic Load: Estimate the number of users and requests your website will handle (e.g., peak vs. normal traffic).
   • Server Specifications: Ensure CPU, RAM, and storage capacity can handle the workload.
   • Scalability: Plan for traffic spikes by using scalable solutions like auto-scaling groups or container orchestration systems (e.g., Kubernetes).
2. Server Type
   • Dedicated Servers: Provide full control and performance but are costlier.
   • Virtual Servers (VPS): Offer a balance between cost and performance.
   • Cloud Servers: Provide flexibility, scalability, and pay-as-you-go pricing.
   • Shared Hosting: Suitable for low-traffic websites but limited in resources and control.
3. Geographic Location
   • User Proximity: Place servers closer to your target audience to reduce latency.
   • Content Delivery Network (CDN): Use a CDN to cache static content across multiple locations for faster delivery.
4. Operating System and Software Stack
   • OS Choice: Choose Linux (e.g., Ubuntu, CentOS) or Windows based on application requirements.
   • Software Compatibility: Ensure the server supports your web stack (e.g., LAMP, MEAN, or Java-based stacks).
   • Database Support: Allocate resources for your database servers (e.g., MySQL, PostgreSQL, Oracle).
5. Load Balancing
   • Distribution of Traffic: Use load balancers to distribute traffic across multiple servers for high availability and fault tolerance.
   • Redundancy: Allocate additional servers as backups in case of failure.
6. Security
   • Firewall and Intrusion Detection: Implement security measures to protect against attacks.
   • Data Encryption: Use HTTPS and secure communication channels.
   • Access Control: Limit access to servers using secure credentials and roles.
   • Backup and Recovery: Plan for regular backups and disaster recovery procedures.
7. Deployment Environment
   • Development, Staging, and Production: Maintain separate environments to ensure testing does not impact live users.
   • CI/CD Pipelines: Automate deployments using Continuous Integration and Continuous Deployment tools.
8. Redundancy and High Availability
   • Failover Mechanisms: Use redundant servers to ensure availability during hardware or software failures.
   • Database Replication: Maintain replicas of your database for redundancy.
9. Monitoring and Management
   • Performance Monitoring: Use tools like New Relic or Prometheus to monitor server health and performance.
   • Logging: Set up centralized logging to track and debug issues.
   • Automation Tools: Use server management tools like Ansible, Chef, or Puppet for provisioning and configuration management.
10. Cost Management
    • Budgeting: Balance performance needs with the available budget.
    • Cloud Services: Consider cost-effective cloud solutions with flexible billing.
11. Compliance
    • Regulatory Requirements: Ensure servers comply with data protection regulations like GDPR, HIPAA, or PCI-DSS.
    • Data Sovereignty: Host data in regions that meet legal and compliance requirements.
12. Backup and Disaster Recovery
    • Backup Plans: Regularly back up critical data and configurations.
    • Recovery Testing: Periodically test your disaster recovery plan.

Properly addressing these considerations ensures a robust, secure, and efficient deployment infrastructure for your website.

A proxy server sits between a client program (typically a Web browser) and an external server (typically another server on the Web) to filter requests, improve performance, and share connections.

1. Mail Server: Almost as ubiquitous and crucial as Web servers, mail servers move and store mail over corporate networks (via LANs and WANs) and across the Internet.
2. Server Platforms: A term often used synonymously with operating system, a platform is the underlying hardware or software for a system and is thus the engine that drives the server.
3. Web Server: At its core, a Web server serves static content to a Web browser by loading a file from a disk and serving it across the network to a user's Web browser. This entire exchange is mediated by the browser and server talking to each other using HTTP.
4. Application Server: Sometimes referred to as a type of middleware, application servers occupy a large chunk of computing territory between database servers and the end user, and they often connect the two.
5. Real-Time Communication Server: Real-time communication servers, formerly known as chat servers or IRC Servers, and still sometimes referred to as instant messaging (IM) servers, enable large numbers users to exchange information near instantaneously.
6. FTP Server: One of the oldest of the Internet services, File Transfer Protocol makes it possible to move one or more files securely between computers while providing file security and organization as well as transfer control.
7. Collaboration Server: In many ways, collaboration software, once called 'groupware,' demonstrates the original power of the Web. Collaboration software designed to enable users to collaborate, regardless of location, via the Internet or a corporate intranet and to work together in a virtual atmosphere.
8. List Server: List servers offer a way to better manage mailing lists, whether they be interactive discussions open to the public or one-way lists that deliver announcements, newsletters or advertising.
9. Telnet Server: A Telnet server enables users to log on to a host computer and perform tasks as if they're working on the remote computer itself.
10. Open Source Server: From your underlying open source server operating system to the server software that help you get your job done, open source software is a critical part of many IT infrastructures.
11. Virtual Server: In 2009, the number of virtual servers deployed exceeded the number of physical servers. Today, server virtualization has become near ubiquitous in the data center. From hypervisors to hybrid clouds, ServerWatch looks at the latest virtualization technology trends.

In the next lesson, you will learn how to estimate a server's transfer load.

Internet servers are classified based on various criteria depending on their functionality, purpose, architecture, and usage. Here are the key criteria:

1. Functionality or Purpose
   • Web Servers: Serve web pages to clients using HTTP/HTTPS (e.g., Apache, Nginx, IIS).
   • Database Servers: Manage and provide access to databases (e.g., MySQL, PostgreSQL, Oracle).
   • File Servers: Store and manage files for access and retrieval (e.g., Samba, FTP servers).
   • Mail Servers: Handle sending, receiving, and storing emails (e.g., Microsoft Exchange, Postfix).
   • Application Servers: Host and run application services (e.g., Apache Tomcat, JBoss).
   • Proxy Servers: Act as intermediaries between clients and other servers (e.g., Squid Proxy).
   • DNS Servers: Resolve domain names to IP addresses (e.g., BIND, Microsoft DNS).
   • Gaming Servers: Support online multiplayer games by managing game sessions and interactions.
2. Hardware and Architecture
   • Dedicated Servers: Entire physical machine dedicated to a specific purpose.
   • Virtual Servers: Virtualized instances running on a physical server (e.g., VPS or virtual private servers).
   • Cloud Servers: Servers hosted in a cloud environment (e.g., AWS, Azure, Google Cloud).
   • Bare-Metal Servers: High-performance physical servers without virtualization layers.
3. Operating System
   • Linux Servers: Operate on distributions like Ubuntu, CentOS, or Red Hat.
   • Windows Servers: Operate on Microsoft Windows Server editions.
   • Unix Servers: Operate on Unix-based systems like Solaris or FreeBSD.
4. Scalability
   • Horizontal Scaling Servers: Multiple servers working together (e.g., in clusters or load-balanced setups).
   • Vertical Scaling Servers: Single servers upgraded with more resources (CPU, memory).
5. Geographic Distribution
   • Local Servers: Hosted on-premises for local access.
   • Global Servers: Hosted in distributed data centers to serve worldwide users (e.g., CDNs like Cloudflare).
6. Accessibility
   • Public Servers: Accessible over the internet by any user (e.g., websites).
   • Private Servers: Restricted to specific users or organizations (e.g., intranet servers).
7. Security and Role
   • Authentication Servers: Handle user authentication and access control (e.g., Active Directory, LDAP servers).
   • Firewall Servers: Monitor and control incoming/outgoing traffic based on security rules.
8. Protocol Support
   • HTTP/HTTPS Servers: Serve content using HTTP or HTTPS protocols.
   • FTP Servers: Provide file transfer capabilities using FTP.
   • SMTP Servers: Handle email delivery using SMTP.
   • SFTP/SSH Servers: Provide secure file transfers and remote access.
9. Usage Context
   • Development Servers: Used in software development for testing and debugging.
   • Production Servers: Handle live workloads in real-world operations.
   • Staging Servers: Used to test applications before deployment to production.
10. Performance and Capacity
    • High-Performance Servers: Optimized for intensive workloads like big data processing.
    • Low-Capacity Servers: Handle lightweight tasks or serve small-scale operations.

By considering these classifications, internet servers can be tailored to meet specific requirements and effectively serve their intended purposes.

1. Web-related server: Mirror, Web, Certificate, Commerce, FTP, Index
2. Mail server: A mail server (also known as a mail transfer agent or (MTA), a mail transport agent, a mail router or an Internet mailer) is an application that receives incoming e-mail from local users (people within the same domain) and remote senders and forwards outgoing e-mail for delivery.
3. Filing server: File, News,Telnet
4. LAN-related server: Directory, Application
5. Dedicated servers: DNS, Proxy

• Dedicated server
  Dedicated server is a service that includes the hardware, software, and ongoing upkeep of a dedicated server.The dedicated server industry often bundles additional services and products with the servers to provide a deeper level of management. Another type of managed service is [vps hosting (virtual private server), this is multiple smaller servers within a larger server under the same hardware. Managed dedicated server providers employ full-time system administrators that maintain dedicated servers. A managed dedicated server allows for not only more productivity, but eases your mind about a multitude of other issues, sometimes unforeseen by the client and even the developers working on functions of the dedicated hosting server. Security is a very large factor in choosing not only a managed dedicated hosting company, but also in choosing a managed dedicated server.