OSPF

Question 1

What two types of authentication does OSPF use?

Answer 1

Plaintext and MD5

Question 2

What protocol number does OSPF use?

Answer 2

89

Question 3

What multicast IP address does OSPF use for the AllSPFRouters group?

Answer 3

224.0.0.5

This address is used for sending OSPF routing updates to all OSPF routers in the network.

Question 4

What MAC address corresponds to the OSPF AllSPFRouters group?

Answer 4

01:00:5e:00:00:05

This MAC address is used in conjunction with the multicast IP address for OSPF communication.

Question 5

How do you enable OSPF with the interface command?

Answer 5

ip ospf process-id area area-id

Question 6

An OSPF advertised default route always appears as what type of route?

Answer 6

an external route

This is a standard behavior in OSPF routing protocols.

Question 7

What is the exception to the rule that an OSPF advertised default route appears as an external route?

Answer 7

when OSPF stub areas are used

Stub areas modify the way routes are advertised in OSPF.

Question 8

What is the default OSPF dead interval in relation to the hello interval?

Answer 8

Four times the hello interval

This setting is crucial for OSPF neighbor relationships and network stability.

Question 9

How can you enable OSPF authentication on all interfaces for an area?

Answer 9

• Configure area authentication in the OSPF process
• Configure the password for each member interface

This ensures that all interfaces within the specified area use the same authentication method.

Question 10

If your neighbors are stuck in the ExStart or Exchange state, what issue might you have?

Answer 10

MTU mismatch

MTU (Maximum Transmission Unit) mismatch can lead to problems in the establishment of neighbor relationships in networking.

Question 11

What command is used to redistribute a static default route into OSPF?

Answer 11

default-information originate

Question 12

What IPv4 or MAC address 01:00:5E:00:00:06 are used for communication with designated routers (DRs)?

Answer 12

224.0.0.6 or 01:00:5E:00:00:06

Question 13

What OSPF state is when neighbors are fully adjacent?

Answer 13

Full

Question 14

Which OSPF state does the DR/BDR election take place?

Answer 14

2-Way

Question 15

Which OSPF external route metric equals the redistribution metric plus the total path metric to the ASBR?

Answer 15

Type 1

Question 16

Which OSPF external route metric equals only the redistribution metric?

Answer 16

Type 2

Question 17

Which OSPF external route type is the default?

Answer 17

Type 2

Question 18

In which OSPF neighbor state are DBD packets exchanged?

Answer 18

Exchange