hardMultiple ChoiceObjective-mapped
XK0-006 Practice Question: During peak hours, a web server experiences…
During peak hours, a web server experiences timeouts. The kernel log shows 'possible SYN flooding'. Which kernel parameter should be increased to mitigate this?
⚠ Common exam trap
Test-takers frequently confuse the SYN backlog queue (`tcp_max_syn_backlog`) with the completed connection backlog (`somaxconn`), leading candidates to choose `net.core.somaxconn` even though it only affects fully established connections, not the SYN flood protection mechanism.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
net.ipv4.tcp_max_syn_backlog
The kernel log message 'possible SYN flooding' indicates that the system's SYN backlog queue is full, causing new connection requests to be dropped. Increasing `net.ipv4.tcp_max_syn_backlog` expands the maximum number of SYN requests that can be queued before the kernel starts dropping them, directly mitigating the issue.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
net.ipv4.tcp_syncookies
Why it's wrong here
Disabling syncookies would worsen the problem.
- ✗
net.core.somaxconn
Why it's wrong here
This is for the maximum number of connections queued for acceptance, not SYN backlog.
- ✓
net.ipv4.tcp_max_syn_backlog
Why this is correct
Increasing this value allows more half-open connections, reducing SYN flooding issues.
- ✗
net.core.rmem_default
Why it's wrong here
This affects receive buffer sizes, not SYN handling.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This XK0-006 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the XK0-006 exam.