What happens if I fail the exam?

You can retake it after a 24-hour cooldown, as many times as you need. Retakes are free, and each attempt draws a fresh random set of questions.

How long is a certificate valid?

The Safeguard Certified Practitioner credential is valid for 24 months from issue. The expiry date is printed on the certificate and shown live on its public verification page. Renewing means passing the current exam again.

Courses

The Network Layer: Logical Addressing, Internet Protocol and Subnetting

IntermediateFree5 modules · 14 lessons · ~2 min

About this course

A working course in Internet Protocol version 4 and version 6 addressing: classless inter-domain routing, subnetting arithmetic you can actually follow, private addressing and network address translation, datagram structure and fragmentation, and address planning that does not collapse as an organisation grows. Every module closes with the security implications of the addressing choices it covers.

What you'll learn

Internet Protocol Version 4 Addressing Fundamentals

Address Structure, Classful History and Why It Was Abandoned
Worked Subnetting Arithmetic: Masks, Network Bits and Host Bits
Network and Broadcast Addresses, and the Arithmetic Mistakes That Break Deployments

Classless Inter-Domain Routing and Subnetting in Practice

Classless Inter-Domain Routing Notation and Route Aggregation
Variable Length Subnet Masking: A Worked Multi-Department Example
A Complete Worked Example: Subnetting an Allocation Across Multiple Sites

Private Addressing and Network Address Translation

Private Address Ranges and Why They Exist
Network Address Translation Mechanics: NAT, PAT and Carrier-Grade NAT
What Network Address Translation Costs: Security and Traceability

Internet Protocol Version 6 and Datagram Structure

Internet Protocol Version 6 Addressing and Address Types
The Internet Protocol Version 4 Header and Fragmentation
The Internet Protocol Version 6 Header and How Fragmentation Changed

Address Planning at Scale and the Security Thread

Address Planning That Does Not Collapse as an Organisation Grows
Internet Protocol Spoofing and the Security Thread Across This Course

01Internet Protocol Version 4 Addressing Fundamentals3 lessons

Address Structure, Classful History and Why It Was Abandoned
Worked Subnetting Arithmetic: Masks, Network Bits and Host Bits
Network and Broadcast Addresses, and the Arithmetic Mistakes That Break Deployments

02Classless Inter-Domain Routing and Subnetting in Practice3 lessons

Common questions

How much does Safeguard Academy cost?

Nothing. Every course, exam, and certificate on the catalog is free — including retakes. All you need is a free Safeguard account.

What are the prerequisites?

None. The flagship course, Safeguard Certified Practitioner, is a beginner-level course — basic familiarity with how software is built helps, but every exam question is answerable from the lessons themselves.