Juniper Exam JN0-637 Topic 1 Question 5 Discussion

Comprehensive Detailed Step-by-Step Explanation with All Juniper Security Reference

Understanding the Scenario:

SRX-1 and SRX-3:

Need to establish an EBGP session through SRX-2.

Issue:

BGP session is not coming up despite correct configurations on SRX-1 and SRX-3.

Option D: The security policy to allow SRX-1 and SRX-3 to communicate on TCP port 179 should be configured.

BGP uses TCP port 179 for establishing sessions.

SRX-2 must have a security policy allowing traffic between SRX-1 and SRX-3 on TCP port 179.

'Security policies must permit BGP traffic (TCP port 179) to allow BGP sessions through the SRX device.'

Source: Juniper TechLibrary - Configuring Security Policies for Transit Traffic

Why Other Options Are Incorrect:

Option A: Host-inbound-traffic affects traffic destined to SRX-2, not transit traffic.

Option B and C: TCP ports 79 and 169 are unrelated to BGP.

Conclusion:

The correct option is D, configuring a security policy to allow TCP port 179.