NAT/PAT Chap 9 Flashcards
What is the primary purpose of NAT?
conserve IPv4 addresses increase network security allow peer-to-peer file sharing enhance network performance
conserve IPv4 addresses
Which method is used by a PAT-enabled router to send incoming packets to the correct inside hosts?
It uses the destination TCP or UDP port number on the incoming packet. It uses the source TCP or UDP port number on the incoming packet. It uses the source IP address on the incoming packet. It uses a combination of the source TCP or UDP port number and the destination IP address on the incoming packet.
It uses the destination TCP or UDP port number on the incoming packet.
What are two benefits of NAT? (Choose two.)
It saves public IP addresses. It adds a degree of privacy and security to a network. It increases routing performance. It makes troubleshooting routing issues easier. It makes tunneling with IPsec less complicated.
It saves public IP addresses.
It adds a degree of privacy and security to a network.
What is a disadvantage of NAT?
There is no end-to-end addressing. The router does not need to alter the checksum of the IPv4 packets. The internal hosts have to use a single public IPv4 address for external communication. The costs of readdressing hosts can be significant for a publicly addressed network.
There is no end-to-end addressing.
What is an advantage of deploying IPv4 NAT technology for internal hosts in an organization?
makes internal network access easy for outside hosts using UDP provides flexibility in designing the IPv4 addressing scheme increases the performance of packet transmission to the Internet enables the easy deployment of applications that require end-to-end traceability
provides flexibility in designing the IPv4 addressing scheme
Refer to the exhibit. Which address or addresses represent the inside global address?
10.1.1.2 192.168.0.100 209.165.20.25 any address in the 10.1.1.0 network
209.165.20.25
Refer to the exhibit. A technician is configuring R2 for static NAT to allow the client to access the web server. What is a possible reason that the client PC cannot access the web server?
Interface S0/0/0 should be identified as the outside NAT interface. Interface Fa0/1 should be identified as the outside NAT interface. The IP NAT statement is incorrect. The configuration is missing a valid access control list.
Interface S0/0/0 should be identified as the outside NAT interface.
A network administrator configures the border router with the command R1(config)# ip nat inside source list 4 pool corp. What is required to be configured in order for this particular command to be functional?
a NAT pool named corp that defines the starting and ending public IP addresses an access list named corp that defines the private addresses that are affected by NAT an access list numbered 4 that defines the starting and ending public IP addresses ip nat outside to be enabled on the interface that connects to the LAN affected by the NAT a VLAN named corp to be enabled and active and routed by R1
a NAT pool named corp that defines the starting and ending public IP addresses
When dynamic NAT without overloading is being used, what happens if seven users attempt to access a public server on the Internet when only six addresses are available in the NAT pool?
No users can access the server. The request to the server for the seventh user fails. All users can access the server. The first user gets disconnected when the seventh user makes the request.
The request to the server for the seventh user fails.
What is defined by the ip nat pool command when configuring dynamic NAT?
the pool of global address the range of internal IP addresses that are translated the pool of available NAT servers the range of external IP addresses that internal hosts are permitted to access
the pool of global address
Refer to the exhibit. What is the purpose of the command marked with an arrow shown in the partial configuration output of a Cisco broadband router?
defines which addresses can be translated defines which addresses are allowed into the router defines which addresses are assigned to a NAT pool defines which addresses are allowed out of the router
defines which addresses can be translated
A network engineer has configured a router with the command ip nat inside source list 4 pool corp overload. Why did the engineer use the overload option?
The company has more private IP addresses than available public IP addresses. The company needs to have more public IP addresses available to be used on the Internet. The company router must throttle or buffer traffic because the processing power of the router is not enough to handle the normal load of external-bound Internet traffic. The company has a small number of servers that should be accessible by clients from the Internet.
The company has more private IP addresses than available public IP addresses.
What are two of the required steps to configure PAT? (Choose two.)
Define a pool of global addresses to be used for overload translation. Create a standard access list to define applications that should be translated. Define the range of source ports to be used. Identify the inside interface. Define the hello and interval timers to match the adjacent neighbor router.
Define a pool of global addresses to be used for overload translation.
Identify the inside interface.
What is the major benefit of using NAT with Port Address Translation?
It allows external hosts access to internal servers. It improves network performance for real-time protocols. It allows many internal hosts to share the same public IPv4 address. It provides a pool of public addresses that can be assigned to internal hosts.
It allows many internal hosts to share the same public IPv4 address.
What is the purpose of port forwarding?
Port forwarding allows an external user to reach a service on a private IPv4 address that is located inside a LAN. Port forwarding allows users to reach servers on the Internet that are not using standard port numbers. Port forwarding allows an internal user to reach a service on a public IPv4 address that is located outside a LAN. Port forwarding allows for translating inside local IP addresses to outside local addresses.
Port forwarding allows an external user to reach a service on a private IPv4 address that is located inside a LAN.
A network administrator is configuring a static NAT on the border router for a web server located in the DMZ network. The web server is configured to listen on TCP port 8080. The web server is paired with the internal IP address of 192.168.5.25 and the external IP address of 209.165.200.230. For easy access by hosts on the Internet, external users do not need to specify the port when visiting the web server. Which command will configure the static NAT?
R1(config)# ip nat inside source static tcp 192.168.5.25 80 209.165.200.230 8080 R1(config)# ip nat inside source static tcp 192.168.5.25 8080 209.165.200.230 80 R1(config)# ip nat inside source static tcp 209.165.200.230 80 192.168.5.25 8080 R1(config)# ip nat inside source static tcp 209.165.200.230 8080 192.168.5.25 80
R1(config)# ip nat inside source static tcp 192.168.5.25 8080 209.165.200.230 80
What is a characteristic of unique local addresses?
They allow sites to be combined without creating any address conflicts. They are designed to improve the security of IPv6 networks. Their implementation depends on ISPs providing the service. They are defined in RFC 3927.
They allow sites to be combined without creating any address conflicts.
Which statement describes IPv6 ULAs?
They conserve IPv6 address space. They are assigned by an ISP. They begin with the fe80::/10 prefix. They are not routable across the Internet.
They are not routable across the Internet.
Refer to the exhibit. Based on the output that is shown, what type of NAT has been implemented?
dynamic NAT with a pool of two public IP addresses PAT using an external interface static NAT with one entry static NAT with a NAT pool
PAT using an external interface
MATCH: step 1 step 2 step 3 step 4 step 5
R1 translates the IP address in the packets from 209.65.200.254 to 192.168.10.10.
R1 replaces the address 192.168.10.10 with a translated inside global address.
R1 checks the NAT configuration to determine if this packet should be translated.
R1 selects an available global address from the dynamic address pool.
The host sends packets that request a connection to the server at the address 209.165.200.254
If there is no translation entry for this IP address, R1 determines that the source address 192.168.10.10 must be translated
step 1 –> The host sends packets that request a connection to the server at the address 209.165.200.254
step 2 –> R1 checks the NAT configuration to determine if this packet should be translated.
step 3 –> If there is no translation entry for this IP address, R1 determines that the source address 192.168.10.10 must be translated
step 4 –> R1 selects an available global address from the dynamic address pool.
step 5 –> R1 replaces the address 192.168.10.10 with a translated inside global address.
A technician is required to configure an edge router to use a different TCP port number for each session with a server on the Internet. What type of Network Address Translation (NAT) should be implemented?
a many-to-one address mapping between local and global addresses
a many-to-many address mapping between local and global addresses
a one-to-many address mapping between local and global addresses
a one-to-one address mapping between local and global addresses
a many-to-one address mapping between local and global addresses
What does the asterisk (*) represent in the following output?
NAT*: s=172.16.2.2, d=192.168.2.1->10.1.1.1 [1]
A. The packet was destined for a local interface on the router.
B. The packet was translated and fast-switched to the destination.
C. The packet attempted to be translated but failed.
D. The packet was translated but there was no response from the remote host.
B. Fast-switching is used on Cisco routers to create a type of route cache in order to quickly forward packets through a router without having to parse the routing table for every packet. As packets are processed-switched (looked up in the routing table), this information is stored in the cache for later use if needed for faster routing processing.
Which of the following are disadvantages of using NAT? (Choose three.)
A. Translation introduces switching path delays.
B. NAT conserves legally registered addresses.
C. NAT causes loss of end-to-end IP traceability.
D. NAT increases flexibility when connecting to the Interne
A, C, E. NAT is not perfect and can cause some issues in some networks, but most networks work just fine. NAT can cause delays and troubleshooting problems, and some applications just won’t work
