Chapter 9: Network Services
TRUE/FALSE
1. Cisco developed NAT, and today the technology is used by routers, firewalls, and even individual
computers with multiple network connections.
2. Static NAT must be used if you want clients outside your network to access services on your servers.
3. The overlapping problem cannot be solved using NAT because NAT hides the internal IP scheme.
4. Most people prefer to use names, not IP addresses, when communicating with network devices.
5. Windows Internet Name Service (WINS) servers are not supported by Cisco routers.
MULTIPLE CHOICE
1. NAT is defined in RFC ____, which describes methods for connecting private (internal) IP addresses
to the Internet.
a.
1022
c.
2145
b.
1133
d.
3022
2. ____ uses a one-to-one mapping or one-to-many mapping method to allow one or more private IP
clients to gain access to the Internet by mapping the private IP addresses to public IP addresses.
a.
DHCP
c.
WINS
b.
NAT
d.
NetBEUI
3. NAT is available in three forms: Static NAT, Dynamic NAT, and ____.
a.
WINS
c.
PAT
b.
DHCP
d.
IP–AT
4. ____ must be used if you want clients outside your network to access services on your servers.
a.
Static NAT
c.
PAT
b.
Dynamic NAT
d.
Dynamic PAT
5. To differentiate between the connections, ____ uses multiple public TCP and UDP ports to create
unique sockets that map to internal IP addresses.
a.
PAT
c.
dynamic NAT
b.
static NAT
d.
virtual NAT
6. You could turn off the lookup feature on a Cisco router by using the ____ command.
a.
no domain–lookup
c.
no ip domain
b.
no ip domain–lookup
d.
no ip lookup
7. NAT servers use ____ to send connections from external clients to the Web server on the internal
network.
a.
nat relay
c.
port relay
b.
port forwarding
d.
dhcp relay
8. ____ is a popular and important naming service.
a.
PAT
c.
DHCP
b.
DNS
d.
NAT
9. The command to configure a DNS lookup on a Cisco router is ____.
a.
ip domain–lookup
c.
ip name–server
b.
ip dns
d.
ip dns–server
10. The ____ command enables DNS if it has previously been disabled.
a.
ip domain–lookup
c.
ip name–server
b.
domain–lookup on
d.
ip dns enable
11. The ____ command is optional, but provides a domain suffix for the names.
a.
ip domain–name
c.
ip domain–suffix
b.
ip suffix–name
d.
ip suffix
12. RARP and ____ servers issue IP configuration information based on a host’s MAC address and require
manual preconfiguration for each host.
a.
WINS
c.
BOOTP
b.
DNS
d.
NetBEUI
13. ____ manages addressing by leasing the IP information to the hosts.
a.
DNS
c.
WINS
b.
DHCP
d.
DNCP
14. DHCP is enabled by default in the Cisco IOS. If you want to make sure it is enabled, use the ____
command at the global configuration mode prompt.
a.
dhcp on
c.
enable service dhcp
b.
enable dhcp
d.
service dhcp
15. Cisco’s DHCP server implementation prefers to save the IP configuration parameters it has sent to a
particular host. These are called ____.
a.
tokens
c.
bindings
b.
overlapping
d.
enablings
16. When monitoring DHCP, the best way to check the bindings is to execute the ____ command on the
router.
a.
show binding
c.
show ip domain–server
b.
show ip dhcp
d.
show ip dhcp binding
17. For information on the specific DHCP address pool, use the ____ command.
a.
show ip pool
c.
show domain pool
b.
show ip dhcp pool
d.
show address pool
18. When you launch the SDM program, you see the Home tab. To see all of the parameters that can be
configured, click the ____ button.
a.
Configure
c.
Tools
b.
Options
d.
Preferences
19. The only difference between using SDM to configure dynamic NAT versus PAT is that in the ____
dialog box, you choose to translate to a single outside interface rather than a pool of addresses.
a.
Select Translation Rule
c.
Address Pool Rule
b.
Add Address Pool
d.
Add Address Translation Rule
20. You can point your router to a DNS server for name resolution simply by configuring the ____
command.
a.
ip name–server
c.
ip dns–server
b.
ip domain dns
d.
ip domain–server
21. Regarding SDM, you access the DHCP configuration area using the ____ button.
a.
DHCP Preferences
c.
Additional Options
b.
Additional Tasks
d.
Services Tasks
COMPLETION
1. ___________________________________ allows many home users, corporations, and organizations
around the world to connect far more computers to the Internet than they would otherwise be able to
connect.
2. ____________________ is the simplest form of NAT, in which a single private IP address is mapped
to a single public IP address.
3. ____________________ means that the NAT router automatically maps a group of valid local IP
addresses to a group of Internet IP addresses, as needed.
4. ____________________ occurs when the internal network has been incorrectly configured for an IP
range that actually exists on the Internet (registered to another entity) or when two companies merge
and each company was using the same private IP address range.
5. By default, a Cisco router will try several times to find an IP address for a name if you enter one. This
automatic translation is called a(n) ____________________.
MATCHING
Match each item with a statement below:
a.
Port address translation
f.
DHCP
b.
Socket
g.
DHCP relay
c.
Static NAT
h.
Security Device Manager (SDM)
d.
DNS
i.
DHCP DISCOVER
e.
ip host command
1. translates names into IP addresses
2. forwarding of a DHCP request
3. a combination of the IP address and port
4. message broadcasted on the network when hosts are configured to use DHCP
5. a one-to-one mapping of private IP addresses to public IP addresses
6. provides IP configuration information to hosts on bootup
7. a special form of dynamic NAT; also known as overloading
8. provides name resolution on a Cisco router
9. a Web-based tool for advanced configuration on Cisco routers
SHORT ANSWER
1. What are the advantages of using private addressing with NAT?
2. What are some of the disadvantages of NAT?
3. Describe static NAT.
4. Describe dynamic NAT.
5. Briefly describe overlapping.
6. What are the steps for configuring dynamic NAT?
7. What are the steps for configuring port address translation?
8. Compare DHCP with RARP and BOOTP.
ANS:
9. Describe the DHCP process.
10. What are the steps for configuring DHCP?
