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303-300 practice examsUpdate in progress

LPIC-3 Security

Linux Professional Institute · expert · 90 minutes

Update in progressLinux Professional Institute now publishes this exam as LPIC-3 Security 303-300 version 3.0, five topic areas worth 60 points; our bank was written for LPIC-3 303 as two broad domains with the exam-version excuse, checked on 21 September 2026. The questions still teach the subject, but the split per domain has moved.

Expert Linux security implemented in practice with specific tools: cryptography and PKI operated through OpenSSL, PAM authentication where a misconfiguration locks everyone out, SELinux and AppArmor mandatory access control confining a compromised process, and LUKS encryption at rest; then netfilter firewalling with default-deny stateful nftables or iptables rules, OpenVPN, WireGuard and IPsec transport with hardened SSH, system hardening as reduce, restrict and update, and AIDE, auditd and rootkit detection catching the compromise that hardening did not prevent.

What you get

180practice questions

3full papers of 60

2course chapters · 12 minutes

100%answers explained

Papers are cut from the bank and weighted like the real exam, and no question appears in two of them. Every wrong answer comes back on later days until you have it right.

What the exam covers

From Linux Professional Institute’s published outline, read on 21 September 2026 (the vendor dates it Invalid Date). Vendor page

Cryptography	28%
Host Security	22%
Access Control	13%
Network Security	28%
Threats and Vulnerability Assessment	8%

Two sample questions

Two of the 180, with the answer and the explanation.

1. Which iptables target rewrites the source address to the outgoing interface's current address?

SNAT --to-source
MASQUERADE — correct
DNAT --to-destination
REDIRECT --to-ports

Why: SNAT is the right choice with a static address, because it does not have to look the address up for every connection.

2. What does the public key allow others to do?

Encrypt to or verify the owner — correct
Decrypt the owner's private data
Sign as the owner
Open the LUKS volume

Why: A public key lets others encrypt messages to the owner or verify signatures the owner made.

The real 303-300 exam

Length	90 minutes
Questions	60
Pass mark	Scaled; LPI does not publish the percentage
Price	Around $200 USD
Recommended before you sit it	An active LPIC-2 certification is required to certify LPIC-3.
Valid for	5 years

Exam facts as published by Linux Professional Institute; always check the vendor’s page before you book.

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