15. IP Services

Question 1

What is the reason that time is synchronized between network devices?

Answer 1

• Managing password
• Encryption key changes
• Checking validity of certificates
• Correlation of security based events
• Troubleshooting network devices

Question 2

What is NTP?

Answer 2

Network Time Protocol UDP 123

Question 3

What concept does NTP use?

Answer 3

Concept of Stratum.
Server connected to the clock is Stratum 1
Clients connected to the server –> Stratum 2 etc

Question 4

What is the maximum number of Stratums?

Answer 4

15

Question 5

What are the command to activate ntp?

Answer 5

ntp master 1

ntp server ip

Question 6

What is root dispersion?

Answer 6

The calculated error of the actual clock attachted to the atomic clock

Question 7

What is the Stratum preference

Answer 7

The device with the lowest Stratum is preffered

Question 8

What are the 3 types of FHRP?

Answer 8

• Hot Standy Routing Protocol
• Virtual Router Redundancy Protocol
• Gateway Load Balancing Protocol

Question 9

What do FHRP do?

Answer 9

The create a virtual IP

Question 10

What is object tracking?

Answer 10

Mechanism for linking with FHRP. Users can track specific objects in het network.

Question 11

What is Hot Standy Routing Protocol?

Answer 11

Cisco protocol for redundancy for IP hosts on ethernet networks. Works with active and standby

Question 12

What happens when an active HSRP router fails?

Answer 12

The standby router takes over with the virtual IP and virutal mac

Question 13

How does the HSRP election goes?

Answer 13

Based on highest priority (default 100)

With tie –> highest IP

Question 14

How many HSRP version are there?

Answer 14

2

v2 supports millisecond timer values

Question 15

What are the HSRP multicast addresses?

Answer 15

224. 0.0.2

224. 0.0.102

Question 16

What are the HSRP mac addresses?

Answer 16

0. 0C07.AC..

0000. 0C9F.F000 –> .FFFF

Question 17

What is Virtual Router Redundancy Protocol?

Answer 17

• Works with master router and back up routers
• Preemption by default
• 2 versions V2-V3 ipv6 included

Question 18

What are the VRRP multicast addresses?

Answer 18

224.0.0.18

Question 19

What are the VRRP MAC addresses?

Answer 19

0000.5500.01..

Question 20

What is Gateway Load Balancing Protocol?

Answer 20

Cisco protocol

Question 21

What are the two roles of GLBP?

Answer 21

AVG - max 1 per group

AVF - max 4

Question 22

What are the 3 supported ways of load balancing?

Answer 22

• Round robin (default)
• Weighted
• Host dependent

Question 23

What are the 4 terms of NAT?

Answer 23

• Inside local
• Inside global
• Outside local
• Outside global

Question 24

What is inside local?

Answer 24

The actual private IP assigned to a device

Question 25

What is inside global?

Answer 25

The public IP that represents one or more inside local IP addresses to the outside

Question 26

What is outside local?

Answer 26

The IP address of an outside host as it appears to the inside network

Question 27

What is outside global?

Answer 27

The public IP assigned to a host on the outside network

Question 28

What are the 3 types of NAT?

Answer 28

• Static - one-to-one
• Pooled - dynamic one-to-one
• PAT - dynamic many-to-one

Question 29

What is the default timeout for NAT translations?

Answer 29

24 hours

Question 30

What are the 2 security concepts of NTP?

Answer 30

• Access list based restriction schemes

- Encrypted authentication mechanism