Infrastructure Services

Question 1

In DNS, what is the Berkley Internet Name Domain (BIND)

Answer 1

Stores different types of resource records used to resolve names.

Question 2

What is an A record

Answer 2

A – end device address

Question 3

What is and NS record

Answer 3

NS - authoritative name server

Question 4

What is a CNAME record

Answer 4

canonical name (or Fully Qualified Domain Name) for an alias, used when multiple services have the single network address but each service has its own DNS entry

Question 5

What is an MX record

Answer 5

mail exchange record, maps a domain name to a list of mail exchange servers for that domain

Question 6

How does DHCP work

Answer 6

Client broadcasts DHCPDISOVER message to identify DHCP servers on the network

DHCP server replied with DHCPOFFER

Client may receive multiple DHCPOFFER messages if there is more than one dhcp server, therefore it DHCPREQUEST message identifies explicit server and lease offer that client is accepting

Assuming IP is available, server returns DHCPACK to acknowledge lease

If lease is no longer valid, due to timeout or another client taking lease, server responds with DHCPNAK (negative ack) message, which means process must start again

Question 7

What is a DHCP server

Answer 7

Provides IP addresses

Question 8

What is a DHCP relay

Answer 8

If no DHCP server is present, can forward DHCP requests to server

Question 9

What is a DHCP client

Answer 9

Receives IP addresses

Question 10

What is NTP

Answer 10

Provides time synchronisation between network devices

Question 11

What is an ACL

Answer 11

Filters traffic at an interface

Question 12

What are the allowed numbers to use for Standard ACLS

Answer 12

1-99

1300-1999

Question 13

Where should a standard ACL be placed

Answer 13

As close to the destination as possible

Question 14

What are the allowed numbers to use for extended ACLs

Answer 14

100-199

2000-2699

Question 15

Where should extended ACLs be placed

Answer 15

As close to source as possible

Question 16

What does NAT do

Answer 16

Translates private to public addresses

Question 17

What are the 3 type of NAT

Answer 17

Static - one to one mapping
Dynamic - many to many
PAT - many to one

Question 18

What is an inside local address

Answer 18

Host address on inside network

Question 19

What is an inside global address

Answer 19

Translated inside local address

Question 20

What is an outside global address

Answer 20

Registered address of internet host

Question 21

What is an outside local address

Answer 21

The address of internet host as it appears on the inside network

Question 22

What are the 3 p’s when it comes to ACLs

Answer 22

one ACL per protocol
one ACL per direction
one ACL per interface

Question 23

What are the 4 DHCP stages, in order

Answer 23

Discover
Offer
Request
Acknowledge

Question 24

At which phase of the DHCP process will a DHCP server provide the client with an IP address, subnet mask, and default gateway?

Answer 24

Offer

Question 25

What is an NTP stratum level

Answer 25

A value between 1 - 15 which indicates NTP priority Lower value indicates higher priority A value of 16 means no clocking is received

Question 26

How do you configure a device as a DHCP server

Answer 26

Create DHCP pool: ip dhcp pool Name define addresses: network [ip subnet]/24 define default gateway: default-router [ip address] select lease time: lease 7 exclude addresses: ip dhcp excluded-address [range]

Question 27

How is static nat configured

Answer 27

ip nat inside source static 10.0.0.19 192.0.2.1

Question 28

How is dynamic nat configured

Answer 28

access-list 10 permit 10.0.0.0 0.0.255.255 ip nat pool MyPool 192.0.2.1 192.0.2.254 prefix-length 24 ip nat inside source list 10 pool MyPool

Question 29

How is PAT configured

Answer 29

ip nat inside source list 11 pool MyPool overload

Question 30

What information can be viewed from using the show ip nat translations command

Answer 30

``` protocol inside local address inside global address outside local address outside global address. ```

Question 31

What information can be view from using the show ip nat statistics command

Answer 31

active translations type of nat being use Inside and outside interfaces

Question 32

What is the benefit of using named IPv4 ACLs over numbered IPv4 ACLs

Answer 32

You can add, delete, and modify entries in a named ACL

Question 33

How is a dhcp relay configured

Answer 33

ip helper-address

Question 34

How do you verify the ip address part of a DHCP pool?

Answer 34

show ip dhcp pool

Question 35

How do the verify the ip address that has been leased to a client

Answer 35

show ip dhcp binding

Question 36

What does CPE stand for

Answer 36

Customer premises equipment