Network server concepts
Key takeaways
- Windows Server suits organisations already standardised on Microsoft technology, Unix is known for stability in demanding, high-uptime environments, and Linux is open source with no per-server licensing cost.
- Servers are compared on features (what is built in), functionality (how well the platform performs the roles actually needed) and suitability (how well it fits existing skills, infrastructure and budget).
- The best platform on paper is the wrong choice if nobody on staff can administer it, so suitability usually decides the platform.
- The core server roles are Active Directory, proxy server, web server, file server, DHCP and DNS; Active Directory is the role most other roles and the whole domain structure depend on.
- Hardware is sized to each role: a file server needs generous, reliable storage, DNS and DHCP need very little storage but very high availability, and a web server scales with expected traffic.
Setting up a network for real, not just designing it on paper (Computer Networks, in the chapter on designing a network), starts with choosing what server platform will actually run it and which specific roles that server will perform. This chapter covers the platform choice, how competing platforms are actually compared, the specific roles a server can run, and the hardware and software each role demands.
Network servers
The operating system family a server runs shapes almost everything else about how it is administered, licensed and supported.
Comparing network servers
| Platform | Licensing cost | Typical strength | Best fit |
|---|---|---|---|
| Windows Server | Per-server or per-user licence | Active Directory, tight Windows-client integration | Organisations standardised on Microsoft technology |
| Unix | Often commercial, vendor-specific | Long-run stability, high-uptime workloads | Legacy enterprise systems with a proven track record |
| Linux | No per-server licence (open source) | Web and cloud infrastructure, configurability | Web servers, cloud workloads, cost-sensitive deployments |
Server roles
Server roles are the specific functions a server can be configured to perform, developed fully in Network Operating Systems, where the operating system is configured, and in Windows Server Roles and Features; the same roles reappear here specifically in the context of choosing and sizing the server that will run them.
Hardware and software requirements
Hardware and software requirements differ by role:
- A file server needs generous, reliable storage.
- A DNS or DHCP server needs relatively little of either but must be highly available.
- A web server's requirements scale with expected traffic.
Requirements are checked against each role's own specification before deployment. This is the same 'size to the role, not a generic figure' discipline already established in Windows Server Roles and Features, applied here at the point of actually choosing hardware for a specific role rather than only planning it.
| Role | Storage demand | Availability demand | Scales mainly with |
|---|---|---|---|
| Active Directory | Low to moderate | Very high | Number of user and computer accounts |
| Proxy server | Moderate (cache) | High | Number of concurrent clients |
| Web server | Low to high, depends on content | High | Expected traffic and concurrent users |
| File server | High, and growing | High | Volume of shared data and number of users |
| DHCP | Very low | Very high | Number of devices needing addresses |
| DNS | Very low | Very high | Number of queries per second |
Choosing a platform and sizing hardware for a growing SACCO branch
A SACCO branch with 30 staff, already using Windows desktops and Microsoft Office, needs a file server and wants to add Active Directory for centralised logins, and separately needs a small web server to host an internal loan-tracking application built by a contractor in a Linux-friendly framework.
Platform for the file server and Active Directory: Windows Server, since the branch's existing skills, desktop platform and the tight Active Directory integration all point toward suitability, not raw technical capability alone; a Unix or Linux domain controller would work technically but poorly fits staff who have never administered one.
Platform for the loan-tracking application: Linux, since the contractor's framework runs natively there, and no licensing cost is needed for a role narrowly scoped to running one web application.
Hardware for the file server: sized generously for storage (branch document and loan file growth over several years) with redundancy (a RAID array), since file services demand high storage and high availability.
Hardware for DNS and DHCP (added to the Windows Server domain controller as additional roles): minimal extra capacity needed, since both demand very little storage, confirming that not every added role needs its own dedicated hardware.
This single scenario uses every element of the chapter together: platform choice by suitability, not raw feature comparison, and hardware sized to what each specific role actually demands, not a single blanket specification applied to every server.
Self-check
(a) Name the three server platform families and state one characteristic strength of each. (3 marks)
(b) Distinguish features, functionality and suitability as ways of comparing network servers. (3 marks)
(c) State six server roles and the function each provides. (6 marks)
(d) Explain why a DHCP server needs very little storage but very high availability. (2 marks)
(e) A branch already runs Windows desktops and wants centralised logins added. Recommend a server platform and justify it using the suitability criterion specifically, not just technical capability. (3 marks)
(f) A file server and a DNS server are both being specified. Explain why they need very different hardware despite both being 'servers'. (2 marks)
Show worked answer
(a) Windows Server: tight integration with Active Directory and Windows clients. Unix: long-established stability in demanding, high-uptime environments. Linux: open source with no per-server licensing cost, dominant for web and cloud infrastructure.
(b) Features are the built-in capabilities a platform offers out of the box. Functionality is how well it performs the specific roles the organisation actually needs. Suitability is how well it fits the organisation's existing skills, infrastructure and budget, not just its technical capability alone.
(c) Active Directory: centralised directory service for users, computers and policy. Proxy server: forwards, filters and caches client requests to the internet. Web server: hosts websites and web applications. File server: provides centralised, shared file storage with access control. DHCP: automatically assigns IP addresses and network configuration. DNS: translates names into IP addresses.
(d) DHCP address leases and configuration data are small, so little storage is needed, but every device on the network depends on it to get online at all, so any outage stops new and renewing devices from reaching the network, making high availability essential despite the low storage demand.
(e) Windows Server, justified by suitability: the branch's staff already use Windows desktops and are familiar with the platform, and Windows Server's tight Active Directory integration directly serves the stated need for centralised logins, a better fit than a technically capable but unfamiliar Unix or Linux alternative.
(f) A file server's demand scales with the volume of shared data and grows continuously, needing generous, redundant storage. A DNS server's data (name-to-address records) is tiny regardless of how many queries it serves, so its demand is on responsiveness and availability, not storage capacity.
Exam tip
Server platform choice (Windows, Unix, Linux) is usually tested through suitability, not raw capability; match a described organisation's existing skills and infrastructure to the platform that fits it, not to whichever platform sounds most advanced, and size hardware to what the specific role actually demands rather than one blanket specification for every server.