JNCIA Security Fundamentals 3

Question 1

What is a prefix-list in Junos and how is it used?

Accepted Answer

A named list of IP prefixes used as a match condition in routing policies or firewall filters

Answer

A prefix-list in Junos is a named set of IP prefixes configured under policy-options. It can be referenced in routing policies (as 'route-filter') and firewall filters as a match condition.

Question 2

In Junos SRX, what is a security zone?

Accepted Answer

A logical grouping of interfaces that share the same security requirements and trust level

Answer

A security zone in Junos SRX is a logical grouping of one or more interfaces that share a common security policy. Traffic between zones is controlled by security policies.

Question 3

What does the 'screen' feature provide in Junos SRX?

Accepted Answer

Protection against network attacks such as SYN floods, ICMP floods, and port scans at the zone level

Answer

Screens in Junos SRX provide stateless attack detection and mitigation at the zone boundary, protecting against DoS attacks, reconnaissance scans, and malformed packets before they reach security policies.

Question 4

In Junos, what is the purpose of the 'policer' action in a firewall filter?

Accepted Answer

To rate-limit traffic that matches the filter term, discarding or marking excess traffic

Answer

A policer attached to a firewall filter term enforces a rate limit (bandwidth limit with burst allowance). Traffic exceeding the limit is either discarded or re-marked with a higher loss priority.

Question 5

Which Junos feature prevents IP spoofing by verifying packets arrive on the expected interface?

Accepted Answer

Unicast Reverse Path Forwarding (uRPF)

Answer

uRPF checks that a packet's source address would be reachable via the same interface it arrived on (strict mode) or via any interface (loose mode), discarding packets that fail this check.

JNCIA - Juniper Networks Certified Internet Associate Practice Test

JNCIA - Juniper Networks Certified Internet Associate Practice Test

JNCIA Security Fundamentals 3