JNCIP-ENT Interior Gateway Protocols — 10 Questions

Question 1

You want to tune OSPF convergence by reducing the hello and dead intervals on a point-to-point interface. Which configuration is valid?

Accepted Answer

set protocols ospf area 0.0.0.0 interface xe-0/0/0.1 hello-interval 1. OSPF interface timers such as hello-interval and dead-interval are configured directly under the interface hierarchy within protocols ospf.

Answer

set protocols ospf area 0.0.0.0 timers hello-interval 1

Answer

set interfaces xe-0/0/0.1 ospf hello-interval 1

Answer

set protocols ospf hello-interval 1 dead-interval 4

Question 2

You are redistributing static routes into OSPF on a Junos device and want to assign a specific metric type to the resulting External LSAs. Where is this metric-type defined?

Accepted Answer

set policy-options policy-statement REDIST-STATIC term 1 then metric-type type-1. External route metric types (Type 1 or Type 2) when redistributing into OSPF are defined under the export policy term's then clause using 'metric-type'.

Answer

set policy-options policy-statement REDIST-STATIC term 1 from external-type 1

Answer

set protocols ospf export REDIST-STATIC metric-type 1

Answer

set protocols ospf redistribute static metric-type 1

Question 3

An OSPF area in your network contains multiple ABRs. You need to suppress the generation of Type-4 summary LSAs into a totally stubby area. How does Junos handle this natively?

Accepted Answer

Totally stubby areas automatically block Type-4 LSAs by design without additional configuration.. Totally stubby areas automatically block Type-3, Type-4, and Type-5 LSAs. No separate command is needed to suppress Type-4 LSAs once an area is defined as a totally stubby area.

Answer

You must apply an export policy on the ABR blocking Type-4 LSAs.

Answer

You must use set protocols ospf suppress-fa to remove Type-4 LSAs.

Answer

You must configure set protocols ospf area <area> stub no-summary-asbr.

Question 4

You need to configure OSPFv2 graceful restart as a helper on a Junos router to assist neighboring routers during their routing engine switchover. Which command enables helper mode?

Accepted Answer

set protocols ospf graceful-restart helper. By default, OSPF graceful restart helper mode is enabled on Junos routers. To explicitly configure or modify it, you use the 'graceful-restart helper' command under protocols ospf.

Answer

set routing-options graceful-restart ospf helper

Answer

set protocols ospf graceful-restart router-role helper

Answer

set protocols ospf helper-mode enable

Question 5

When configuring OSPFv3 authentication, which mechanism is natively utilized in modern Junos implementations since OSPFv3 relies on IPv6 AH/ESP or OSPFv3 Authentication Trailer (RFC 7166)?

Accepted Answer

set protocols ospf3 authentication-trailers sa-name AUTH-KEY. Junos supports the OSPFv3 Authentication Trailer defined in RFC 7166, configured via the authentication-trailers command under protocols ospf3.

Answer

set protocols ospf3 area 0.0.0.0 interface xe-0/0/0.0 md5 key 123

Answer

set protocols ospf3 security ipsec spi 256

Answer

set protocols ospf3 interface xe-0/0/0.0 password 123

Question 6

You need to ensure that an OSPF interface does not send or receive OSPF hellos, but its subnet is still advertised into the OSPF domain. What configuration achieves this in Junos?

Accepted Answer

set protocols ospf area 0.0.0.0 interface em0.0 passive. Configuring an interface as passive prevents OSPF protocol packets from being sent or received on that interface while still including its network prefix in the routing updates.

Answer

set protocols ospf area 0.0.0.0 interface em0.0 silent

Answer

set protocols ospf passive-interface em0.0

Answer

set protocols ospf area 0.0.0.0 interface em0.0 disable-hellos

Question 7

You are configuring OSPF domain-id when redistributing routes between OSPF and BGP (or multiarea setups). Which configuration statement sets the OSPF domain identifier?

Accepted Answer

set protocols ospf domain-id 10.0.0.1. The domain-identifier for OSPF (often used in MPLS VPNs or inter-AS scenarios) is configured under protocols ospf using the domain-id statement.

Answer

set protocols ospf area 0.0.0.0 domain-identifier 10.0.0.1

Answer

set routing-options autonomous-system 65000 ospf-domain 10.0.0.1

Answer

set protocols ospf bgp-domain-identifier 10.0.0.1

Question 8

You are troubleshooting an OSPF network where virtual links are deployed to connect a non-backbone area to Area 0 across a transit area. Which statement is true regarding virtual link configuration in Junos?

Accepted Answer

set protocols ospf area 0.0.0.1 virtual-link transit-area 0.0.0.2 neighbor-id 192.168.10.1. Virtual links require you to specify the area ID of the transit area and the router ID of the remote endpoint (the other ABR) under protocols ospf.

Answer

set protocols ospf area 0.0.0.2 transit-link neighbor 192.168.10.1

Answer

set protocols ospf virtual-link neighbor 192.168.10.1 area 0.0.0.1

Answer

set protocols ospf virtual-router 192.168.10.1 transit-area 0.0.0.2

Question 9

You are tasked with summarizing internal OSPF routes on an Area Border Router (ABR). Which configuration statement accomplishes route summarization for an area?

Accepted Answer

set protocols ospf area 0.0.0.1 area-range 10.10.0.0/16. Internal route summarization on an OSPF ABR in Junos is configured using the 'area-range' statement under the specific area hierarchy.

Answer

set protocols ospf summary 10.10.0.0/16 area 0.0.0.1

Answer

set protocols ospf area 0.0.0.1 aggregate 10.10.0.0/16

Answer

set routing-options aggregate route 10.10.0.0/16 ospf

Question 10

You need to prevent an OSPF interface from participating in Designated Router (DR) election, forcing it to always act as a DROTHER, even if it has the highest priority. How is this achieved in Junos?

Accepted Answer

set protocols ospf area 0.0.0.0 interface xe-0/0/0.0 no-dr-election. Setting the OSPF interface priority to 0 prevents the router from participating in DR/BDR elections and forces it to become a DROTHER.

Answer

set protocols ospf area 0.0.0.0 interface xe-0/0/0.0 disable-dr

Answer

set protocols ospf area 0.0.0.0 interface xe-0/0/0.0 drother-only