单选题Which of the following is used to reduce the number of public IP addresses required?（）A RADIUSB SNATC PATD NAT

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第3题：

A company has recently switched ISPs and is being assigned a new block of public addresses.  The public web and FTP servers must be re-addressed to support this change.  After changing IP addresses and updating the DNS records many customers have reported that they are not able to access the web or FTP servers.  Which of the following could have been done prior to making these changes to make it more transparent to users？（）

• A、Reduce the TTL on the DHCP records.
• B、Configure a primary DNS server for the PTR records.
• C、Reduce the TTL on the DNS records.
• D、Configure a caching only DNS server.

正确答案:C

第4题：

What will happen if a private IP address is assigned to a public interface connected to an ISP?（）

• A、Addresses in a private range will be not routed on the Internet backbone.
• B、Only the ISP router will have the capability to access the public network.
• C、The NAT process will be used to translate this address in a valid IP address.
• D、Several automated methods will be necessary on the private network.
• E、A conflict of IP addresses happens, because other public routers can use the same range.

正确答案:A

第5题：

Which of the following types of NAT allows multiple private internal IP addresses to use a singlepublic external IP address？（）

• A、NAT mapping
• B、NAT overloading
• C、NAT caching
• D、Static NAT
• E、Dynamic NAT
• F、Overlapping NAT

正确答案:B

第6题：

Which of the following network devices uses NAT to convert private IP addresses into public IPaddresses?（）

• A、NAS
• B、Firewall
• C、Hub
• D、Bridge

正确答案:B

第7题：

A company has a corporate office building that is used by 50 to 100 unique visitors each day for meetings. Users routinely report that they are unable to access the network with their laptops when visiting this location. The help desk reports that these users are not getting IP addresses automatically assigned. After an investigation， the server administrator has determined that the DHCP service is functioning， but a minimal number of addresses are available for lease. The building is on its own class Csubnet and has 250 addresses in the scope.  Which of the following represents a long term solution tothe problem？（）

• A、 Manually delete address leases from DHCP.
• B、 Create reservations in DHCP for users frequently visiting this location.
• C、 Assign static IP addresses to visiting laptops.
• D、 Reduce the lease duration in the DHCP scope options to one day.

正确答案:D

第8题：

What is the purpose of a network mask?（）

• A、It is used to identify the maximum hop count of a subnetwork.
• B、It is used to identify an IP address as either private or public.
• C、It is used to identify the network to which an IP address belongs.
• D、It is used to identify the total number of bits present in an IP address.

正确答案:C

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第14题：

Which one of the following varieties of NAT utilizes different ports to map multiple IP addresses to a single globally registered IP address?（）

• A、Static NAT
• B、Port loading
• C、NAT Overloading
• D、Dynamic NAT
• E、None of the above

正确答案:C

第15题：

Which of the following describe private IP addresses? (Choose two.)（）

• A、addresses chosen by a company to communicate with the Internet
• B、addresses that cannot be routed through the public Internet
• C、addresses that can be routed through the public Internet
• D、a scheme to conserve public addresses
• E、addresses licensed to enterprises or ISPs by an Internet registry organization

正确答案:B,D

第16题：

Which of the following describe private IP addresses?（）

• A、addresses chosen by a company to communicate with the Internet
• B、addresses that cannot be routed through the public Internet
• C、addresses that can be routed through the public Internet
• D、a scheme to conserve public addresses
• E、addresses licensed to enterprises or ISPs by an Internet registry organization

正确答案:B,D

第17题：

Which of the following describe private IP addresses?（）

• A、Addresses chosen by a company to communicate with the Internet.
• B、Addresses that cannot be routed through the public Internet.
• C、Addresses that can be routed through the public Internet.
• D、A scheme to conserve public addresses.
• E、Addresses licensed to enterprise or ISPs by an Internet registry organization.

正确答案:B,D

第18题：

Which of the following is used to reduce the number of public IP addresses required?（）

• A、RADIUS
• B、SNAT
• C、PAT
• D、NAT

正确答案:D

第19题：

An IP address is 198.37.16.23.  Which of the following router’s IP addresses should be used to route traffic to the 193.130.56.0 network？（）

• A、193.130.56.0
• B、198.37.16.15
• C、198.130.16.15
• D、198.130.56.15

正确答案:B

第20题：

Which statement is true about source NAT？（）

• A、Source NAT works only with source pools.
• B、Destination NAT is required to translate the reply traffic.
• C、Source NAT does not require a security policy to function.
• D、The egress interface IP address can be used for source NAT

正确答案:D

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