问题 单项选择题

某公司局域网通过ISP提供的宽带线路与Internet相连,其网络连接方式及相关的网络参数如图7-1所示。其中,ISP分配给该公司的公网IP地址为202.117.12.32/29。


该公司有一台需对外发布公共信息的Web服务器,则其部署的位置以及相应的网络改进措施是______。
由于受一些条件因素变化的影响,电信部门分配给该公司的公网IP地址变更为102.117.12.32/30,则规划师对图7-1所示的网络连接最可能采取的应对措施是______。

A.无需改动图7-1所示的网络连接方案,只需重新调整代理服务器的NAT配置参数
B.将代理服务器与宽带Modem直接连接,去掉区域(B)
C.在宽带Modem的下连端口串入一台新增的代理服务器(或数据交换专用服务器)
D.去掉代理服务器,将区域(A)、(B)合并为同一区域并使用地址块10.X.X.X重新规划该区域的IP地址

答案

参考答案:B

解析: 区域(B)所接入的计算机将使用公网IP地址直接访问Internet,该区域计算机所分配的IP地址应与代理服务器外网卡的IP地址同处一个网段。同时考虑到ISP分配的公网IP地址为202.117.12.32/29,其中“/29”是子网掩码的缩写形式,表示子网掩码的前29位为“1”,其对应的点分十进制数是255.255.255.248。该网段共有232-29-2=23-2=6个可用的IP地址(202.117.12.33~202.117.12.38),扣除已作为该网段网关地址的1个IP地址(202.117.12.33),再扣除已分配给代理服务器外网卡的IP地址(202.117.12.34),那么区域(B)计算机可用的IP地址范围是202.117.12.35~202.117.12.38,子网掩码是255.255.255.248,默认网关地址是202.117.12.33。
由于IP地址为192.168.0.35的计算机属于区域(A),需要通过代理服务器连接到Internet,因此其发送到Internet上的IP数据包的源IP地址为202.117.12.34。IP地址为202.117.12.35的计算机属于区域(B),其发送到Internet上的IP数据包的源IP地址没有经过地址变换,以202.117.12.35源IP地址的形式在Internet中出现。
如果将对外发布公共信息的Web服务器部署在图7-l的区域(B),则该单位的客户、潜在用户和外部访问者无需通过该单位的内网就可以直接获得他们所需要的关于公司的一些信息。同时建议该单位通过相关技术,将区域(B)部署成防火墙中的DMZ区(即非军事区),允许外网用户有限度地使用其中的资源,又可保障该Web服务器的安全。
如果电信部门分配的公网IP地址为202.117.12.32/30,其中“/30”表示子网掩码的前30位为“1”,其对应的点分十进制数是255.255.255.252,该网段共有232-30-2=22-2=2个可用的IP地址(202.117.12.33、202.117.12.34),而IP地址202.117.12.33已作为连接电信部门的网关地址,IP地址202.117.12.34已作为代理服务器外网卡的IP地址,已没有空闲的公网IP地址可用,则图7-1的区域(B)中不能再接入使用公网IP地址直接访问Internet的计算机。因此需将代理服务器与宽带Modem直接连接,即将区域(B)去掉,使代理服务器与Internet属于点对点的连接方式。

单项选择题 A3/A4型题
单项选择题

Some of the concerns surrounding Turkey’s application to join the European Union, to be (1) on by the EU’s Council of Ministers on December 17th, are economic--in particular, the country’s relative poverty. Its GDP per head is less than a third of the average for the 15 pre-2004 members of the EU. (2) it is not far off that of Latvia--one of the ten new members which (3) on May 1st 2004, and it is much the same as (4) of two countries, Bulgaria and Romania, which this week concluded (5) talks with the EU that could make them full members on January 1st 2007.

(6) , the country’s recent economic progress has been, according to Donald Johnston, the secretary-general of the OECD, stunning. GDP in the second quarter of the year was 13.4% higher than a year earlier, a (7) of growth that no EU country comes close to (8) . Turkey’s (9) rate has just fallen into single figures for the first time since 1972, and this week the country (10) agreement with the IMF on a new three-year, $10 billion economic program that will help Turkey (11) inflation toward European levels, and enhance the economy’s resilience.

Resilience has not historically been the country’s economic p point. (12) , throughout the 1990s growth oscillated like an electrocardiogram (13) a violent heart attack. This (14) has been one of the main reasons why the country has failed dismally to attract much-needed foreign direct investment. Its stock of such investment is lower now than it was in the 1980s, and annual (15) have scarcely ever reached $1 billion.

One deterrent to foreign investors is due to (16) on January 1st 2005. On that day, Turkey will take away the right of virtually every one of its citizens to call themselves a millionaire. Six zeros will be removed from the face value of the lira (里拉,土耳其货币单位); one unit of the local (17) will henceforth be worth what 1 million are now--ie, about £ 0.53 (0.53 欧元). Goods will have to be (18) in both the new and old lira for the whole of the year, (19) foreign bankers and (20) can begin to look forward to a time in Turkey when they will no longer have to juggle mentally with indeterminate strings of zeros.

15()

A.inflows

B.imports

C.exports

D.outputs