13.11.5 - Proxy Servers - Practice Questions

You connect your computer to a wireless network available at the local library. You find that you can't access several websites you need to on the internet. Which of the following is the MOST likely cause of this problem? ------------------------------------------------------------------------ Port triggering is redirecting traffic to the wrong IP address. A firewall is blocking ports 80 and 443. A proxy server is filtering access to websites. The router has not been configured to perform port forwarding.

A proxy server is filtering access to websites. ---------------------------------------------------- A proxy server can be configured to block internet access based on website or URL. Many schools and public networks use proxy servers to prevent access to websites with objectionable content. Ports 80 and 443 are used by HTTP to retrieve all web content. If a firewall were blocking these ports, access would be denied to all websites. Port forwarding directs incoming connections to a host on the private network. Port triggering dynamically opens firewall ports based on applications that initiate contact from the private network.

Which of the following functions are performed by proxy servers? (Select TWO). ------------------------------------------------------------------------- Block employees from accessing certain websites Filter unwanted email Block unwanted packets from entering your private network Store client files Cache web pages

Block employees from accessing certain websites Cache web pages -------------------------------------------------------- A proxy, or proxy server, stands between client computers and web servers. You can use a proxy server to prevent access to specific websites, or to cache (save) frequently used web pages. When a proxy receives a request from the client, it checks to verify that the client is allowed access to the website. If allowed, it then checks its cache to see if the requested page is in the cache. If the page is already cached, then the proxy server fulfills the request by displaying the requested page from the cache rather than retrieving it from the internet. Receiving a web page from a local proxy server is much faster than downloading the page from the internet.

Two employees are unable to access any websites on the internet, but can still access servers on the local network, including those residing on other subnets. Other employees are not experiencing the same problem. Which of the following actions would BEST resolve this issue? ---------------------------------------------------------------------- Use ipconfig to confirm that APIPA has not assigned an IP address. Reconfigure the clients to send all traffic directly to the ISP, bypassing the proxy server. Identify the proxy server name and port number in Internet Options. Identify the filter settings on the proxy server for specific internet sites.

Identify the proxy server name and port number in Internet Options. ---------------------------------------------------------- In this case, you should identify the proxy server name and port number in Internet Options. Windows automatically detects and uses a proxy server if one is on the network. If the proxy server is not detected, you should manually configure the proxy settings. If you bypass the proxy server, the clients are no longer managed by the proxy server. This is not a recommended solution. Because other users are not experiencing the same problems, the filtering settings on the proxy server for specific internet sites are probably not the cause of the problem. IP addresses assigned by APIPA force the client to the 169.254.0.0 subnet. This would prevent the client form accessing internal servers that use static IP addresses, especially those on different subnets.

You would like to control internet access based on users, time of day, and websites visited. Which of the following actions would BEST meet your criteria? ----------------------------------------------------------------------- Configure the Local Security Policy of each system to add access restrictions based on time of day and content. Enable Windows Firewall on each system. Add or remove exceptions to control access based on time of day and content. Install a proxy server. Allow internet access only through the proxy server. Configure internet zones using Internet Options. Configure a packet-filtering firewall. Add rules to allow or deny access based on time of day and content.

Install a proxy server. Allow internet access only through the proxy server. --------------------------------------------------------- Use a proxy server to control internet access based on users, time of day, and websites visited. You configure these rules on the proxy server, and all internet access requests are routed through the proxy server. Use a packet filtering firewall, such as Windows Firewall, to allow or deny individual packets based on characteristics such as source or destination address and port number. Configure internet zones to identify trusted or restricted websites and to control the types of actions that can be performed when going to those sites.

An after-school care center allows children to browse the internet. They want to limit the websites that the children can access. Which of the following network hosts would MOST likely provide this service? --------------------------------------------------------- Web server Proxy server DHCP server Print server

Proxy server ---------------------------------- One function of a proxy server is to intercept request from a client browser, and either forward it on to the internet or deny access to the internet site. A print server manages network printers and makes them available to computers throughout the network. Print jobs are sent to the print server instead of directly to the printer. A web server offers web pages to clients. Many organizations have their own web server which is accessible from the internet or from the internal network. A DHCP server leases IP addresses to client computers when they first connect to the network.

You need to configure a Windows workstation with the IP address of the proxy server for your network. Click the tab in the Internet Properties window that you would use to do this. [General - Security - Privacy - Connections - Programs - Advanced]

To configure the IP address of the proxy server, go to Control Panel > Network and Internet > Internet Options. Click the Connections tab and then select LAN settings. In the dialog displayed, you can enable a proxy server for the LAN and then enter the proxy server's IP address and port number.