JN0-106 Cheat Sheet

#	Domain	Weight	Questions	Practice
1.0	Networking Fundamentals	16%	48	Practice →
2.0	Junos OS Fundamentals	17%	92	Practice →
Total	33%	528

Domain

Weight

Questions

Practice

1.0

Networking Fundamentals

16%

Practice →

2.0

Junos OS Fundamentals

17%

Practice →

Total

33%

528

Domain Quick Reference

1.0Networking Fundamentals

Candidates must map protocols to OSI/TCP-IP layers, calculate subnets, and read Junos interface output like show interfaces and show arp. Get subnetting right: correct masks, network, broadcast, and usable host ranges.

16%

Key concepts

✓Mapping protocols like ARP, ICMP, TCP and UDP to OSI and TCP/IP layers
✓IPv4 addressing, subnet masks, CIDR notation and host/network range calculation
✓Junos interface naming and status shown by show interfaces terse
✓Ethernet concepts including MAC addressing, frames, and collision/broadcast domains

Watch out for

⚠Confusing OSI layer numbers with TCP/IP layers, for example placing ARP at Layer 3 instead of Layer 2
⚠Calculating usable hosts by forgetting to subtract the network and broadcast addresses from 2^n
⚠Assuming a Junos interface is up when show interfaces terse shows only the link up but protocol down

2.0Junos OS Fundamentals

Use Junos CLI operational mode and configure mode to edit the candidate config, then verify with show | compare and commit check before commit. The critical skill is understanding commit semantics: candidate versus active configuration and rollback.

17%

Key concepts

✓Roles of the Routing Engine and Packet Forwarding Engine, and the rpd and mgd daemons
✓Difference between candidate configuration and active configuration, and what commit does
✓Junos CLI hierarchy: operational mode versus configuration mode, and edit/exit navigation
✓Configuration groups, apply-groups, and how inherited statements appear in the final config

Watch out for

⚠Assuming the candidate configuration takes effect immediately; changes stay inactive until commit, and rollback 0 restores the last committed config.
⚠Confusing the Routing Engine's control-plane work with the PFE's forwarding work, or thinking both run on the same hardware in all platforms.
⚠Believing operational-mode commands like show interfaces can be run from configuration mode, or that config commands work in operational mode.

Exam Day Reminders

→Read every question stem fully — look for qualifiers like 'MOST likely,' 'BEST,' or 'EXCEPT.'

→Flag uncertain questions and come back — don't waste time on one question.

→Eliminate obviously wrong options first, then choose between remaining ones.

→Trust your first instinct unless you have a specific reason to change.

→For JN0-106, scenarios typically have one clearly best answer — look for the option that matches the specific constraints in the question.

#	Domain	Weight	Questions	Practice
1.0	Networking Fundamentals	16%	48	Practice →
2.0	Junos OS Fundamentals	17%	92	Practice →
Total	33%	528

Domain

Weight

Questions

Practice

1.0

Networking Fundamentals

16%

Practice →

2.0

Junos OS Fundamentals

17%

Practice →

Total

33%

528

Domain Quick Reference

1.0Networking Fundamentals

16%

Key concepts

✓Mapping protocols like ARP, ICMP, TCP and UDP to OSI and TCP/IP layers
✓IPv4 addressing, subnet masks, CIDR notation and host/network range calculation
✓Junos interface naming and status shown by show interfaces terse
✓Ethernet concepts including MAC addressing, frames, and collision/broadcast domains

Watch out for

⚠Confusing OSI layer numbers with TCP/IP layers, for example placing ARP at Layer 3 instead of Layer 2
⚠Calculating usable hosts by forgetting to subtract the network and broadcast addresses from 2^n
⚠Assuming a Junos interface is up when show interfaces terse shows only the link up but protocol down

2.0Junos OS Fundamentals

17%

Key concepts

✓Roles of the Routing Engine and Packet Forwarding Engine, and the rpd and mgd daemons
✓Difference between candidate configuration and active configuration, and what commit does
✓Junos CLI hierarchy: operational mode versus configuration mode, and edit/exit navigation
✓Configuration groups, apply-groups, and how inherited statements appear in the final config

Watch out for

⚠Assuming the candidate configuration takes effect immediately; changes stay inactive until commit, and rollback 0 restores the last committed config.
⚠Confusing the Routing Engine's control-plane work with the PFE's forwarding work, or thinking both run on the same hardware in all platforms.
⚠Believing operational-mode commands like show interfaces can be run from configuration mode, or that config commands work in operational mode.

Exam Day Reminders

→Read every question stem fully — look for qualifiers like 'MOST likely,' 'BEST,' or 'EXCEPT.'

→Flag uncertain questions and come back — don't waste time on one question.

→Eliminate obviously wrong options first, then choose between remaining ones.

→Trust your first instinct unless you have a specific reason to change.

→For JN0-106, scenarios typically have one clearly best answer — look for the option that matches the specific constraints in the question.

JN0-106 Exam Blueprint — At a Glance

Domain Quick Reference

1.0Networking Fundamentals

2.0Junos OS Fundamentals

Exam Day Reminders

More JN0-106 resources

JN0-106 Cheat Sheet

JN0-106 Exam Blueprint — At a Glance

Domain Quick Reference

1.0Networking Fundamentals

2.0Junos OS Fundamentals

Exam Day Reminders

More JN0-106 resources