Topic 5 - DNS

Question 1

What protocol and port number does DNS use?

Answer 1

UDP

Port 53

Question 2

Two types of DNS lookups?

Answer 2

Forward lookup - the host asks about a domain name and an IP address is returned

Reverse lookup - the host asks about an IP address and a domain name is returned

Question 3

Default least time on DHCP server.

Answer 3

1 day

Question 4

What Interface does Cisco IOS DHCP relay agent supports?

Answer 4

unnumbered interfaces

Question 5

Which Cisco IOS command will indicate that interface GigabitEthernet 0/0 is configured via DHCP?

Answer 5

show ip interface GigabitEthernet 0/0

Question 6

Which statement about the nature of NAT overload is true?

Answer 6

applies a one-to-many relationship to internal IP addresses

Question 7

command can you enter to display duplicate IP addresses that the DHCP server assigns?

Answer 7

show ip dhcp conflict 10.0.2.12

Question 8

DHCP relay

Answer 8

DHCP relay agent is any host that forwards DHCP packets between clients and servers.

Question 9

DHCP Client

Answer 9

Cisco IOS DHCP client enables a device to obtain an IP address from a DHCP Server dynamically using the DHCP protocol.

Question 10

DHCP Server

Answer 10

Cisco IOS DHCP Server feature is a full DHCP Server implementation that assigns and manages IP addresses from specified address pools within the router to DHCP clients.

Question 11

What are the details does DHCP offer message contain?

Answer 11

IP address
Domain name
lease

Question 12

What type of message are DHCP DISCOVER and DHCP OFFER?

Answer 12

DHCP DISCOVER - Broadcast Message
and
DHCP OFFER - Unicast Message.

Question 13

DHCP protocol standard?

Answer 13

RFC 2131

Question 14

What TFTP is used to identify an external server that will be used to store the DHCP bindings database.

Answer 14

TFTP 150

Question 15

is HSRP a Cisco proprietary protocol?

Answer 15

YES

Question 16

Explain HSRP

Answer 16

Hot Standby Routing Protocol (HSRP) enables high availability by providing multiple default gateways with the same virtual IP address to hosts on a LAN.

Question 17

Default priority on a HSRP?

Answer 17

Default priority is 100.

Remember highest number represents the highest priority

Question 18

Range of HSRP

Answer 18

1 to 255

Question 19

Preamble on HSRP

Answer 19

If preemption is enabled, the router with the highest priority becomes the active router
If priorities are equal, the current active router does not change

Question 20

What multicast address does HSRP v1 uses to send hello packet?

Answer 20

224.0.0.2

Question 21

What multicast address does HSRP v2 uses to send hello packet?

Answer 21

224.0.0.102

Question 22

Group of HSRP V1 and V2

Answer 22

V1 is 0 to 255

V2 is 0 to 4095

Question 23

what happens when an interface running HSRP 1 gets an packet from HSRP 2?

Answer 23

Packet is ignore

Question 24

Command to see real-time Translation on the router?

Answer 24

Debug ip nat

Question 25

Command to show all the translation?

Answer 25

#Show ip nat translations

Question 26

3 methods of NAT

Answer 26

1 - Static 2 - Dynamic 3 - Overload

Question 27

PAT address translation also called as?

Answer 27

NAT Overload

Question 28

Explain NAT?

Answer 28

Network Address Translation (NAT) is used to map private IP addresses on a LAN to a public IP address(es) on the outside interface of the router

Question 29

The interface of the router connecting to the LAN network is?

Answer 29

``` NAT #ip nat inside ```

Question 30

The interface of the router connecting to the WAN is?

Answer 30

``` NAT Outside #ip nat outside ```

Question 31

Explain PAT?

Answer 31

Port-address translation Commonly used for overloading. An extension to NAT that permits multiple IP addresses on a LAN to be mapped to a single public IP address

Question 32

What is the local IP address of a private host on your network (e.g., a workstation's IP address) called?

Answer 32

Inside Local

Question 33

What is the public IP address that the outside network sees as the IP address of your local host called?

Answer 33

Inside Global

Question 34

What is the local IP address from the private network, which your local host sees as the IP address of the remote host. called?

Answer 34

Outside local

Question 35

Explain NTP ?

Answer 35

The Network Time Protocol (NTP) synchronizes the time of day among a set of distributed time servers and clients

Question 36

What transport protocol does NTP use?

Answer 36

UDP

Question 37

What used in NTP to describe the distance between a device and the time source?

Answer 37

Stratum

Question 38

What is a disadvantage of NAT?

Answer 38

There is no end-to-end addressing.

Question 39

The Inside Local address is usually what?

Answer 39

An RFC 1918 address

Question 40

Which type of NAT maps a single inside local address to a single inside global address?

Answer 40

static

Question 41

The four steps in obtaining a lease are?

Answer 41

1 - DHCPDISCOVER 2 - DHCPOFFER 3 - DHCPREQUEST 4 - DHCPACK (if success)

Question 42

The DHCPv6 REPLY packet is what type? (broadcast, multicast, unicast)

Answer 42

Unicast

Question 43

What is dynamic NAT?

Answer 43

- Automatically map IP to IP | - Typically a pool of available address

Question 44

What is Overloading NAT?

Answer 44

- Automatically map many IPs to one IP | - Uses ports to track individuals from many

Question 45

___________specifies allowed IP for NAT rule

Answer 45

Access List