CCNA 4E Chapter 7
IP Addressing Services - DHCP / NAT
V 4.0 March 2008
7.0.1.1
7.1.1.1
7.1.2.1
List three temporary solutions allowing
network users to use IPv4 addresses
rather than moving to IPv6:
What are the three main items issued to
a host by a DHCP server?
In this chapter DHCP is not referred to as
an IP Address saving tool, but as a ___
___ tool.
In what type of environment (military or
civilian) would a router be useful as a
DHCP server?
What are the three different DHCP
allocation methods?
Explain DHCP Operations from the point
where a host searches for a DHCP
Server:
7.1.3.1
7.1.3.2
7.1.3.3
In general, how are messages
transmitted from the Client to the DHCP
Server?
In general, how are messages
transmitted from the DHCP Server to the
Client?
What are the two messages sent from
the Client to the DHCP Sever using
“Unicast”?
If the Client-1 hears that Client-2 has
already responded to the same DHCP
Server Offer, how will Client-1 respond to
the DHCP Server’s Offer? In this case
what will happen next for Client-1?
If Client-1 sends a DHCPRequest to the
DHCP Server and the DHCP Server has
already given the address to another
Client, how will the DHCP Server
respond to Client-1?
Describe the three main differences
between DHCP and its predecessor
BOOTP:
What message field is ignored by older
BOOTP systems?
What ports are used by the Client and
the DHCP Server?
Developed by General Dynamics
1
Manual Allocation: The administrator assigns a pre-allocated
IP address to the client and DHCP only communicates the IP
address to the device.
Automatic Allocation: DHCP automatically assigns a static IP
address permanently to a device, selecting it from a pool of
available addresses. There is no lease and the address is
permanently assigned to a device.
Dynamic Allocation: DHCP automatically dynamically
assigns, or leases, an IP address from a pool of addresses
for a limited period of time chosen by the server, or until the
client tells the DHCP server that it no longer needs the
address.
DORA
DHCPDiscover
DHCPOffer
DHCPRequest
DHCPAcknowledge
Broadcast
Unicast
DHCP Release
DHCP Discover (if the Client comes online and already is
programmed with the address of the DHCP Server).
With a DHCPDecline
DORA process will begin again
DHCPNack
DORA process will begin again
DHCP Options
Client 67
Server 68
CCNA 4E Chapter 7
IP Addressing Services - DHCP / NAT
V 4.0 March 2008
7.1.4.1
7.1.4.2
7.1.6.1
7.1.8.3
7.2.1.1
7.2.2.1
7.2.2.2
7.2.2.3
When the DHCP process is complete,
the Server has acknowledged the
address leased to the Client, what
message field is updated to bind the
address to the Client?
What is the command to remove a single
IP address from the DHCP pool to
prevent them from being issued to
Clients/Hosts? Range of IP addresses?
What are the series of commands used
to create a DHCP pool and issue the
three basic components a Client needs
to communicate on the LAN?
What are the commands for the following
DHCP features:
DNS, DOMAIN, VoIP
What command can be used to see how
many addresses the DHCP Server has
successfully issued?
What command can be used to see what
IP address has been assigned to specific
MAC Addresses?
What command can be used to show
information about IP to MAC bindings as
well as information about the number of
addresses issued?
What command is used to retrieve an IP
address from the DHCP Server when it is
not on the local segment with the
requesting Client?
What command can be used to watch
DHCP functions on the server in realtime?
What are the private IP address ranges
for A,B,C as defined by RFC 1918?
What is NAT?
In what type of network environment is
NAT usually found?
In a NAT environment private addresses
are considered to be ____ and public
address are considered to be ____?
To where are non-routable address not
allowed to be routed?
What are the two forms of NAT
mapping? Give an example of how each
is used.
What is the ratio of private to public
address translations with NAT?
NAT Overload allows more than one
private address to translate to a single
public address. This is known as _____.
What is the ratio of private to public
address translation with NAT Overload?
Developed by General Dynamics
2
CIADDR
ip dhcp excluded-address a.b.c.d
ip dhcp excluded-address a.b.c.d w.x.y.z
ip dhcp pool NAME
network a.b.c.d m.m.m.m
default-router g.g.g.g
dns-server a.b.c.d
domain-name us.army.mil
option 150 ip a.b.c.d
show ip dhcp server statistics
show ip dhcp binding
show ip dhcp pool
ip helper-address x.x.x.x
debug ip dhcp server events
A 10.0.0.0 - 10.255.255.255
B 172.16.0.0 - 172.31.255.255
C 192.168.0.0 - 192.168.255.255
10.0.0.0/8
172.16.0.0/12
192.168.0.0/16
Stub network on Border Gateway Router
Inside / Outside
ISP
1:1
PAT
M:1
CCNA 4E Chapter 7
IP Addressing Services - DHCP / NAT
V 4.0 March 2008
7.2.3.1
Even though PAT can handle up to
65536 private addresses to one public IP
address, what is the recommended
maximum ration?
Does the source port address in PAT
traverse the network to the destination?
List some benefits of using NAT/PAT?
4000:1
Yes, but the destination is only concerned with the first 32
bits of an address.
List some drawbacks to using NAT/PAT?
7.2.4.1
What commands are used to statically
map the following private address to the
public address using NAT?
10.0.0.10 / 24 and 141.63.7.20 / 28
c# ip nat inside source static 10.0.0.10 141.63.7.20
c# int f 0/0
ip nat inside
c# int s 0/0/0
ip nat outside
7.2.5.1
What commands are used to dynamically
assign the following private address to
the public addresses using NAT?
10.0.0.10 / 24 and 141.63.7.16 / 28
c# ip nat pool PUBLIC 141.63.7.16 141.63.7.31 netmask
255.255.255.0
c# ip nat inside source list 1 pool PUBLIC
c# ip access-list 1 permit 10.0.0.0 0.0.0.255
c# int f 0/0
ip nat inside
c# int s 0/0/0
ip nat outside
7.2.6.1
How would the previous question be
answered using PAT?
“show ip nat translations” will display
what information?
“clear ip nat translation *” will perform
what function?
“debug ip nat” will display what
information?
How many unique addresses are
available using IPv4?
How many unique addresses are
available using IPv6?
Who is driving the move to IPv6 in the
US?
Why is IPv6 more secure than IPv4?
c# ip nat inside source list 1 pool PUBLIC overload
IPv4 has 32 bits across 4 Octets, how is
an IPv6 address constructed?
The representation or writing of an IPv6
address can be shortened by leaving out
“zeros” or “unspecified” addresses by
using what format?
Some “Service Providers” are using both
IPv4 and IPv6 on their core networks. If
this is not an option, how would you
connect two IPv6 networks across the
enterprise/”cloud”?
What is meant by “Dual Stacked”?
How do you enable IPv6 routing on a
router?
128 bits across 8 fields of 16 bits each
7.2.8.1
7.2.8.2
7.3.1.1
7.3.1.3
7.3.2.1
7.3.3.1
7.3.4.1
7.3.7.1
Developed by General Dynamics
3
4,294,967,296
3.4 x 10³ IP addresses
DoD
::