3.2.2. Networked Host Services
š” First Principle: To improve efficiency, security, and manageability, you should centralize common services like file sharing, printing, and authentication on dedicated servers.
Scenario: In an office, instead of every user managing their own files and printers, you set up a central file server for shared storage using SMB, a print server to manage all print jobs, and a DHCP server to manage IP addressing.
Networked hosts provide services that are shared by many clients.
- Server Roles:
- DNS Server: Resolves domain names.
- DHCP Server: Assigns IP addresses.
- File Server: Provides centralized file storage and sharing (e.g., using SMB).
- Print Server: Manages print jobs sent to shared printers.
- Mail Server: Handles sending and receiving email.
- Web Server: Hosts websites (e.g., Apache, Nginx, IIS).
- Syslog Server: A centralized server for collecting log messages from network devices.
- AAA Server: Provides Authentication, Authorization, and Accounting for network access (e.g., RADIUS).
- Internet Appliances:
- UTM (Unified Threat Management): An all-in-one security appliance that combines a firewall, antivirus, intrusion detection, and other security functions.
- Load Balancer: Distributes incoming traffic across multiple servers to improve performance and reliability.
- Proxy Server: An intermediary server that forwards requests from clients to other servers. Can be used for content filtering, caching, and anonymity.
ā ļø Common Pitfall: A single point of failure. If you have only one DNS server or one file server and it goes down, the entire network or a critical service will be impacted. Redundancy is key for critical services.
Key Trade-Offs:
- Centralized (Server) vs. Decentralized (Peer-to-Peer): Centralized services are easier to manage, back up, and secure. Decentralized services have no single point of failure but are much harder to manage.
Reflection Question: What are the main benefits of using a dedicated print server in an office with 50 employees and 5 printers, compared to having each employee connect to each printer directly?