Testing network security: test plans and best practices
In short: A test plan defines what will be tested, how success is judged, when, by whom, with what and how. Testing every device against expected results, then making recommendations, proves the network is secure and working. Best practices such as segmentation, logging and correct device placement keep it that way.
Why test the network?
A network isn't secure just because it was configured carefully. Testing proves that every device and the environment as a whole behave as intended: firewalls, servers, domain controllers, email servers, routers, switches, gateways and password policies. A test plan sets out the scope, approach, criteria, schedule, responsibilities, resources and procedures.
Define the objectives
- Volume testing: works smoothly under normal production volumes over long periods.
- Stress testing: copes with the maximum expected load all at once; a common rule is to test with about 25% more than the expected peak.
- Recovery testing: backups and recovery procedures actually work.
- Security testing: the network meets its security requirements (access, filtering, encryption, logging, vulnerabilities).
- Performance testing: response times and throughput meet their targets; check connection speeds and network cards too.
Criteria, schedule, people, resources and procedures
- Acceptance criteria: for example, all expected results achieved on the first run; all severe and high-priority faults fixed and retested; a documented plan for remaining low and medium faults.
- Schedule: main activities with start and finish dates.
- Responsibilities: who is involved and what each person does.
- Resources: staff, hardware and software needed, matched against the deployment plan.
- Procedures: how test cases and scripts are prepared, how the test environment is set up, how tests are run and results verified.
Recording tests
Each test needs test data, an expected result and the actual result. A simple template:
| No. | Test | Test data / method | Expected result | Actual result | Pass/Fail |
|---|---|---|---|---|---|
| 1 | Guest VLAN isolation | From a guest PC, connect to a staff server | Connection blocked | ||
| 2 | SSH only on switch | Try Telnet then SSH to the management IP | Telnet refused, SSH prompts for login | ||
| 3 | Port security | Connect an unknown laptop to a secured port | Port err-disabled, alert logged | ||
| 4 | Firewall policy | Scan the public IP from outside | Only approved ports open | ||
| 5 | Backup recovery | Restore a server configuration from backup | Device restored and working |
Use the results to write recommendations for improving security in that environment.
Network security best practices
- Understand the OSI model and the role of each network device.
- Know your defences and place security devices correctly.
- Segregate the network into zones and VLANs.
- Don't disable personal (host) firewalls.
- Use centralised logging and analyse logs immediately.
- Allow-list approved web domains where practical, and send workstation web traffic through a proxy.
- Monitor and baseline normal protocol behaviour to spot anomalies.
- Use VPNs for remote and site-to-site access.
- Consider using different vendors for different defence layers.
- Use IDS/IPS properly and tune them.
- Physically secure network equipment.
Practice
What is the difference between volume and stress testing?
What three things must every test record?
Key takeaways
- A test plan covers scope, approach, criteria, schedule, responsibilities, resources and procedures.
- Test for volume, stress, recovery, security and performance.
- Record test data, expected and actual results, then make recommendations.
- Best practices: segment, log centrally, place devices correctly, use VPNs and IPS, secure equipment physically.
Original content written by Mohamed Fayas for FM TecHub. © 2026 FM TecHub. You're welcome to share a link to this page; please don't copy the text elsewhere without permission.