Networking Fundamentals ch 6-10 (100 ?)

Which of the following associates a port number with a host on a private network. NAT VLSM CIDR PAT

(PAT) Port address translation Associates a port number with the translated address. Use PAT to allow multiple private hosts to share a single public address. Each Private host is associated with a unique port number.

Which of the following solutions would you implement to track which websites network users are accessing. Proxy NIDS Packet Filtering firewall

Proxy A proxy server is a device stands intermediary between a secure private network and the public. It stops and inspects every packet at the firewall, which causes a break between the client and the source server.

A switch recieves a fram addresses to the MAC address FF:FF:FF:FF:FF:FF what will the switch do with the frame? Process the fame and respond to the sending device drop the frame. Forward it out the port and the devices with that MAC address Send it out to all ports except for the port it was received on

Send it out all ports except to the port it was received on. The MAC address FF:FF:FF:FF:FF:FF identifies the broadcast address, meaning all hosts on the subnet. Switches forward broadcast frames out all ports except for the port on which the frame was received on.

Which of the following protocols is an open source protocol used by most manufactures of VoIP systems. Session initiation protocol(SIP) User data gram protocol (UDP)

Session initiation protocol. (SIP) is used to set up, maintain and tear down multimedia communications.

Your are designing an update to your clients wireless network. The existing wireless network 802.11b equipment; which your client complains runs to slow. She wants to upgrade to the network to run up to 600 Mbps. Due to budget constraints, the client wants to upgrade only wireless network boards in her users workstations. She has also indicated that the systems must continue to function during the transition periods Which 802. 11 standard will work best in this situation? 802.11d 802.11b 802.11n

802.11n Provides up tp 600 Mbps

Select the statement that best describes a broadcast storm A broadcast storm occurs when the amount if electrical interference on a cable exceeds acceptable levels, broadcasting a storm of noise and preventing accurate data transfer. A broadcast storm occurs when there are so many broadcast messages on the network that they approach or exceed the network bandwidth.

A broadcast storm occurs when there are so many broadcast messages on the network that they approach or exceed the network bandwidth.

Your company has a connection to the internet that allows users to access the internet. You also have a web server and an email server that you want to make available to internet users. You want to create a DMZ for these two servers. IPS Network -based firewall VPN concentration. IDS

Network based firewall

Which of the following routing protocols uses relative link cost as a metric? BGP EIGRP RIO OSPF

OSPF IS a link state routing protocol used for routing within AS. OSPF used relative link cost for the metric.

Which of the following routing protocols divides the network into areas with all networks required to have an area 0 (area 0 identifying the backbone area)? RIP ISIS OSPF EIGRP

OSPF OSPF divides a large network into areas. Each autonomous system requires an area 0 that identifies the network backbone. All areas are connected to the area 0, either directly or indirectly through another area. Routes between areas must pass through area 0

Switching Loop

Occurs when there are multiple active paths between switches.

You are setting up a wireless hotshot in a local coffee shop. For the best results you want to disperse the radio signals evenly throughout the the coffee shop. Which of the following antenna types would you use on the AP to provide a 360 degree dispersed wave pattern? Multi-Directional Multi_Pint Omni-Directional Directional

Omni-directional An omni directional antenna provides a 360-degree dispersed wave pattern . In this configuration, signals are dispersed evenly through in all directions.

Which of the following best describes the platform as a serves (PassS) cloud computing service model? Paas delivers infrastructure to the client such as processing, storage, networking and virtualized environments. Paas delivers everything a developer needs to building an application onto the cloud infrastructure.

Paas delivers everything a developer needs to building an application onto the cloud infrastructure. The deployment comes with out the cost and complexity of buying and managing the underlying hardware and software layers.

Which of the following is a firewall function? Encrypting Packet Filtering FTP hosting

Packet Filtering Check packets on set of admin defined criteria. If not accepted then it is dropped.

Which of the following features us used with digital IP phones to supply power through a switch port? Trunking PoE VPN Spanning tree

PoE PoE supplies power to end devices through the Rj45 Ethernet switch port. Power to the phone is carried on unused wires within the drop cables.

Which of the following techniques allows incoming traffic addressed to a specific port to move through a NAT router and be forwarded to a specific host? Port forwarding Port address translation Spanning tree protocol EIGRP

Port forwarding Port forwarding is a a type of static NAT implementation where a specific port is mapped to private IP address.

Your computer has an IP address of 161.13.5.15. Your computer is on a: Multi-cast network Private Network Public Network

Public Network

You want to implement 802.1x authentication on your wireless network. Which of the following will be required? WPA2 Radius TKIP WPA

RADIUS

You need to configure a spanning tree on a Cisco switch. You like to use protocol that conforms to the 802.1w standards. PortFast PortFast Rapid PVST+

Rapid PVST+

You have a company network that is connected to the Internet. You want all users to have Internet access, but need to protect your private network and users. You also need to make a Web server publicly available to Internet users. Which solution should you use? Use a single firewall. Put the Web server in front of th firewall and the private network behind the firewall. Use firewalls to create a DMZ . Place the we server inside the DMZ and the private network behind the DMZ

Use firewalls to create a DMZ . Place the we server inside the DMZ and the private network behind the DMZ

You run a small network for your business that has a single router connected to the Internet and a single switch. You keep sensitive documents on a computer that you would like to keep isolated from other computers on the network. Other hosts on the network should not be able to communicate with this computer through the switch, but you still need to access the network through the computer. What should you use for this situation? VLAN VPN Spanning tree

VLAN

You need to keep in all other dept from accessing servers used by the financial dept. Which of the following technologies should you use to logically isolate the network? VLANS MAC filtering NIC teaming.

VLANS

In the lobby of your building are 4 RJ45 ports connected to the switch. You want to allow visitors to plug into these ports to gain internet access, but they should not have access to any other devices on your private network. Likewise employees connected throughout the rest of the building should have both private and Internets access. Which feature should you implement. Spanning tree Poe Port authentication VLANS

VLANS Use VLANS to segregate hosts based on switch ports. Use port authentication for control access to the network.

You need to provide DHCP and file sharing services to a physical network. These services should be deployed using virtualization. Which type of virtualization should you implement? Virtual desktops Network as a Service Virtual servers Virtual Networks

Virtual Servers Server virtualization runs multiple instances if a server operating system on a single physical computer. With a server virtualization, you migrate servers on older hardware to newer computers or add virtual servers to computers with extra unused hardware resources.

What component is most likely ti allow physical and virtual machines to communicate with each other. Virtual Switch Virtual desktop Host operating system

Virtual Switch A virtual hard disk is a file that is created within the host operating system and simulates a hard disk for the virtual machines.

You Manage a network that uses a single switch. All ports within your building connect through the single switch. In the lobby of your building are three RJ45 ports Connected to the switch. You want to allow Visitors to plug into these ports to gain internet access, but they should not have access to any other devices on the private network. Employees concerted throughout the rest of the building should have both private and internet access access. Which feature should you implement? NAT Port authorization DMZ Vlans

Vlans Use vlans to segregate hosts based on switch ports, You can define two Vlans, one for employees connected through out the building and another for the ports in the lobby. The ports in the lobby would have only internet access, while devices connected to the ports in the rest of the building could communicate with other devises with the same Vlans. Use Port Authorization to control access to the network based things such as username and password.

Which of the following benefits apply only to creating VLANS with switches and not segmenting the network with regular switches? You can create multiple domains You can create multiple collision domains.

You can create multiple broadcast domains.

What info does the next hop entry in a routing table identify? The last router to the path to the detestation network. The first router in the path to the destination network.

The first router in the path to the destination network.

Which of the following protocols is used by VoIp to set up maintain and terminate a phone call? SIP RTP TLS

(SIP) The Session initiation It is used to set up, maintain, tear down and redirect phone calls

Which of the following cloud computing solutions will dilver software applications to a client either over the internet or a local area network? IaaS SaaS PaaS DaaS

(Saas) Software as a service delivers software applications to the client either over the internet or local area network

Which of the following is not one of the ranges of IP address defines in RFC 1918 that are commonly used behind a NAT Server? 169.254.0.1 - 169.254.255.254 192.168.0.1 - 192.168.255.254 10.0.0.1- 10.255.255.254 172.16.0.1 - 17.31.255.254

169.254.0.1 - 169.254.255.254 169.254.0.1 - 169.254.255.254 is the range of IP address assigned to windows DHCP clients if a DHCP server does not assign the client an IP address. This range is known as the Automatic Private IP Addressing (APPIPA) range

Which of the following IP addresses is a valid IP address for a host on a public Network?

172.16.254.12 PRIVATE (142.15.6.1) Public 10.31.125.2 PRIVATE 192.168.16.45 PRIVATE

Which command would you use on a switch to enable management form a remote network. Ip address dhcp No shutdown Ip default-gateway 192.168.10.185

192.168.10.185 To enable management from a remote network, configure the default gateway. Use the following command in global mod: Switch(config)#ip default-gateway IP_address

How many total channels are available for 802.11a wireless network? 3 11 12 23 54

23 802.11a wireless uses the 7.75 GHz range has a tottal 23 channels 802.11b and 802.11g 2.GHz which has a total of 11 channels of the U.S.

What is the frequency if 802.11a networking? 900 MHz 1.2 GHz 2.4 GHz 5.75 GHz

802.11a 802.11b and 803.11g operate in the 2.4 GHz range.

You are designing an update to your clients wireless network. The existing wireless network uses 802.11g equipment, which your client complains the runs too slowly. She wants to upgrade the network to run 150 Mbps or faster? Which 802.11 standard will work best in this situation? 802.11d 802.11b 802.11a 802.11n

802.11n 802.11n is the best choice for the client. 802.11a operates at max speed of 54 Mbps. 802.11a is not compatible with 802.11g network boards. 802.11b runs at only 11 Mbps. 802.11n access points are backwards compatible with 802.11g equipment and run at the speeds of up to 600 Mbps.

What key advantages does a virtual router have over a physical router? Faster routing performance Allows the virtual router redundancy protocol to be used Multiple networks can be connect to a single interface.

Multiple networks can be connect to a single interface. The key advantage of a virtual router is that is can support multiple networks on a single router interface.

In virtualization, what is the role of a hypervisor? A hyper visor has the actual hardware in place on the machine, such as the hard disk drives, optical drive, RAM, and motherboard. A hypervisor allows machines to interact with the hardware without going through the host operating system. A hypervisor is created within the host operating system and simulates a hard disk for the virtual machine.

A hypervisor allows virtual machines to interact with the hardware without going through the host operation system. A hypervisor is a thin layer of software that resides between the virtual operating systems and hardware. A hypervisor allows virtual machines to interact with the hardware without going through the host operating system and manages CPU, Storage and Ram.

All in one security appliance is the best suited for which type of implementation? A credit card company that stores customer data. A remote office with no on site technician. An office with dedicated network closet.

A remote office with no on site technician

What is a soft phone? A device that converts fax calls and other soft call between PSTN an IP network A traditional or VoIP phone that has a padded handset that is more comfortable for a user. A software application that runs on a computer or other device that access a VoIP server make real time phone calls

A software application that runs on a computer or other device that access a VoIP server make real time phone calls A soft phone is software that is installed on a computing device such as a computer or handheld device.

Which of the following does a router acting as a firewall use to control which packets are forwarded or dropped ACL RDP VNC PPP

ACL (access control list) ACL statment include an action to either allow or deny the traffic specified by the ACL statement.

Which of the following characteristics of static routing when compared to dynamic routing. All routes must be made manually on the router Routers use the hop count to identify the distance to a destination network.

All routes must be manually updated on the router

What is the least secure place to locate an access point with an omni-directional when creating a wireless cell. In the center of the building Above the 3rd floor In the common or community work areas Near a Window

Near a window The least secure for a wireless cell access point is against a perimeter wall. Because it leaks the signal outside the intended use.

Which of the following routing protocols is used by routers in the internet for learning and sharing routes? IS-IS RIP BGP

BGP ISPS used BGP to identify routes between ASs. A very large networks can use BGP initially, but typically only share routers on the internet.

Which of the following routing protocols uses paths, rules and polices instead of a metric for making routing decisions? RIP ISIS OSPF BGP

BGP It is an advanced distance vector protocol that uses, paths, rules, and polices to make routing decisions instead of a metric.

You manage network with a single switch. On each switch port a hub connects multiple devices to the switch.. Which conditions are you most likely to experience on the network? Cross talk Echo Collisions

Collisions A collision occurs when two devices that share the same media segment transmit at the same time. In a switch network, collision should only occur on port that have multiple devices attached. To eliminate collisions, connect only a single device to each switch port.

You have configured a wireless access point to create a small network. For security you have disabled SSID broadcast. From the client computer you try to browse to find the access point. You see some other wireless networks in the area but cannot see your network. What should you do? Enable the wireless card on the client Configure a profile on the wireless client Decrease the beacon interval on the access point.

Configure a profile on the wireless client. When a networks SSID single is turned off you must enter manually on a system for a connection.

What does the IP address dhcp command allow you to do? Specify the DHCP relays server for forwarding DHCP packets. Send the DHCP server address to all connected devices. Configure the switch to obtain an IP address from the DHCP server.

Configure the switch to obtain an IP address from the DHCP server.

Which of the following prevents access based on website ratings and classifications? DMZ Packet filtering firewall Content filter

Content filter An intern content filter software is used to monitor and restrict what content is delivered to an end user across the web companies, schools, libraries and families commonly use content filters to restrict internet access, block specific website.

You have a network configured to use OSPF routing protocol. Which of the following describes the state when all OSPF routers have learned about all other routes in the network. Convergence VLSM Link state Distance Vector Classful

Convergence Convergence takes place when all routers have learned about all other routes in the network

Which firewall implementation creates a buffer network that can be used to host email or web servers? DMZ ACL

DMZ Web servers and email servers can be placed in this buffer network so that they can be access from the internet.

Wireless clients seem to take to long to find the wireless access point. You want to reduce the time it take for clients to connect What should you do? Decrease the beacon interval Enable SSID broadcast

Decrease the beacon interval To improve access times, decrease the beacon interval.

You find that the computer computer can communicate with hosts on the same subnet but not with hosts on different subent. No other computers are having a problem. Which configuration values would you most likely need to change? IP address DNS server Default gateway

Default gateway The default gateway value is used for sending packets other subents.

Which of the following best describes the concept of VLAN? Devices on the same network logically grouped as if they where on separate networks Devices on different networks can receive multicast packets.

Devices on the same network logically grouped as if they where on separate networks

Which of the following measures will make your wireless invisible to the casual attacker performing war driving? Change the default SSID Disable the SSIID Use a form of authentication other than open authentication.

Disable SSID Disabling SSID the broadcast single you can increase the chances of not being hacked but their are many ways around if someone wanted to connect to the network.

Which of the following enterprises wireless deployment models uses access points with enough intelligence to allow the creation of guest WLANS for keeping public wireless traffic separate from private traffic? Lightweight access point with wireless controller infrastructure. Independent access points Hub-and-Spoke infrastructure Distributed wireless mesh infrastructure.

Distributed wireless mesh infrastructure. A distributed wireless mesh architecture moves some of the network intelligence from the controller out to the individual access points. In this configuration, the controllers is no longer a bottleneck. The APs are smart enough to communicate directly with each other to create more efficient paths for network traffic.

A wireless network consists of multiple 802.11 access points that are configured as follows: SSID(HIDDEN): CorpNET Security: WPA2-PSK Frequency: 5.7 Ghz Bandwith Per channel: 20MHz The network is required to support an ever increasing number of devices. To ensure there is sufficient capacity, you want to maximize the available network bandwidth? What should you do? Upgrade to 802.11a access points implement antenna diversity Double the bandwidth assigned per channel to 40 MHz

Double the bandwidth assigned per channel to 40 MHz 802.11n access points provide an option to allocate double the bandwidth per channel increasing it to 40 MHz which results in double the data rate.

A user reports that the network from her workstation is very slow. The problem does not seem to be affecting any other users. Which of the following conditions is the most likely cause? Switching loop Incorrect VLAN Duplex mismatch Broadcast storm

Duplex mismatch a duplex mismatch occurs when two devices are using different duplex settings. In this case, one device will try to transmitting using full duplex, while the other will expect half duplex communications. Switching loops occur when there are multiple active paths between two switches

You want to connect your small company network to the Internet. Your ISP provides you with a single IP address that is to be shared between all hosts on your private network. You do not want external hosts to be able to initiate connection to internal hosts. What type of NAT should you implement? Static Shared Dynamic

Dynamic Use a dynamic NAT to share public addresses with multiple private hosts.

Which of the follwing routing protocols is classfied as a hyprid routing protocol EIGRP RIP OSPF ISIS

EIGRP EIGRP is a hybrid routing protocol developed by Cisco for routing within an AS.

You are the administrator of a growing network. You notice the network you have created is broadcasting, but you cannot ping systems on different segments of your network . What devices should you use to fix the issue? Range extender Access point Network Bridge

Network Bridge A NB is used to connect different segments of a network.

You manage a network with multiple switches. You find that your switches are experiencing heave broadcast storms. Which of the following will help reduce the affects of a broadcast storm? Configuring each switch with a single trunk port. Disable auto-duplex detection Enable spanning tree on switches.

Enable spanning tree in the switches. A broadcast is excessive broadcast traffic that renders normal network communication impossible. Broadcast storm Spanning tree The spanning tree is a protocol on a switch that allows the switch to maintain multiple links that would form a switching loops can be caused by switching loops that cause broadcast traffic to be circulated endlessly between switches or denial of services.

Which of the following features are supped by WPA2 on a wireless network ? Network Identification Encryption Traffic filtering based on packet characteristics.

Encryption WiFi protected access provides encryption and user authentication for wireless networks.

Which of the following is the best device to protect your private network from a public untrusted network. Gateway Firewall Router Hub

Firewall

What type of virtualization completely simulates a real physical host? Partial virtualization Semi virtualization Full virtualization

Full virtualization

You have been asked to find a business service that would accommodate the current size of the company, but would also be able to scale as the company grows. Which cloud services model should they use? Daas SaaS IaaS PaaS

IaaS IaaS delivers infrastructure to the client such as processing, storage, networks. The clients deploys and runs software without purchasing secrets, data center space or network equipment.

Because of unique construction of your organizations facility, there are many locations that do not have a clear line of sight between network clients ans access points. As a result radio singles are reflected along multiple path before finally being received. The result is distorted signals that interfere with each other. What should you do? Switch to RADIUS authentication for wireless clients. Implement antenna diversity. Install directional access points.

Implement antenna diversity.

A switch is running STP is in the learning state. A message destined for a different network arrives at the switch. Which of the following best describes what the switch will do? It uses the source MAC address and network segment information to build its bridge database, but does not forward the messages. It does not record address or segment information. It does not forward the message.

It uses the source MAC address and network segment information to build its bridge database, but does not forward the messages. A switch in the learning state will build its database through the information it receives from incoming messages. However it does not forwards message. Remember devices forward messages only if they are in the forwarding state.

Your company uses VoIP for phone calls. Recently employees have been complaining about calls with unusual sound effects Which type of problem is occurring on the VoIP system? Latency Echo Jitter

Jitter

Switching running STP are in the process of exchanging BPDUS and redefining their roles. Which port are the switches currently in? Listening Learning Forwarding

Listening

Which if the following do switches and wireless access points use to control access through a device. MAC filtering Session Filtering Port number filtering

MAC Filtering Both switches and wireless access points are layer 2 devices, meaning they use the Mac address to make forwarding decisions. Both devices typically include some form of security that restricts access based on MAC address.

You have a router configured to share information using RIP. In addition, you have a single static route that identifies a default route for all other networks. The next hop router for the default route has changed. You need to make change with least amount if effort possible. What should you do? Stop and restart the RIP protocol on the router. Force RIP to perform an immediate update. Manually reconfigure the default route to point to the new next ho router.

Manually reconfigure the default route to to the next hop router With a static route. when changes to the network occur, routing table entries must be modified, added or removed manually.

When multiple routes to a destination exits, what is used to select the best possible route? Metric Exterior gateway protocol

Metric The metric can be calculated based in hop count, bandwidth or link cost.

You mange a network with Multiple subents connected to the internet. A user reports that she cant access the internet . You investigate the problem and find that she can access all hosts on the private network but no hosts in the internet. Which of the following is likely cause if the problem? Switching loop on the users subnet Duplex mismatch between a switch and router Missing defaults route on a router.

Missing default route on a router If you can access all private subnets but no the internet then troubleshoot the connection to the internet

You manage a network with two switches. The switches are connected together through their Gigabit Ethernet Up-link ports. You define VLAN1 and VLAN2 on each switch. A device on the first switch in VLAN1 needs to communicate with a device on the same swithc is in VLAN2. What should you configure so that the two devices can communicate? Routing Mirroring Trunking Spanning tree

Routing In a typical configuration with multiple VLANS and singe or multiple switches, workstations in one VLAN will not be able communicate with workstations in other VLANS. To enable inter-VLAN communication you will need to use a router.

You have physically added a wireless access point to your network and installed a wireless networking card in two laptops running windows Neither laptop can find the the network. It has to be manually entered. Which of the following values identifies the network AP? WEP SSID Channel

SSID The SSID is the name of the wireless network

You are configuring a wireless network with two wireless access points. Both access points connect to the same weird network. You want wireless users to be able to connect ether access point and have the ability to roam between the the two access points. How should you configure the access points? Different SSID, Same Channel Same SSID, different channel Different SSID, Different channel

Same SSID, different channel Use diffent channels to avoid overlapping but same SSID.

You mange a network that uses multiple switches. You want to provide multiple paths between switches so that if one link goes down, an alternative path is available. Which feature should your switch support? Trunking Spanning tree PoE Mirroring OSPf

Spannig tree Spanning tree allows the switch to maint multiple paths between used switches within a subnet.

Which if the following solutions would you implement to eliminate switching loops. Auto Duplex Spanning tree CSMA/CD

Spanning tree Run the spanning tree protocol to prevent switching loops.

You manage a single subnet with 3 switches. The switches are connected to provide redundant paths between the switches. Which feature prevents switching loops and ensures there is only a single active path between any two switches.? Spanning tree PoE Bonding Trunking 802.1x

Spanning tree is a protocol on a switch that allows the switch to maintain multiple paths between a switches within a subnet. The spanning tree protocol runs in each switch and is used to select a single path between any two switches.

Which of the following features dynamically places switch ports in blocking or forwarding states? Spanning tree Trunking PoE Mirroring

Spanning tree. The Spanning protocol on a switch that allows the switch to maintain multiple paths between switches within a subset. The spanning tree protocol runs in each switch and is used to select a single path between any two switches.

You are the network administrator for a small company that implements NAT to access the Internet. However, you recently acquired 5 servers that must be accessible from outside your network. Your ISP has provided you with 5 additional registered IP addresses to support these new servers but you don't want the public to access these servers directly. You want to place these servers behind your firewall on the inside network yet still allow them to be accessible to the public from the outside. Which method of NAT translation should you implement for these 5 servers? Overloading Dynamic Static Restricted

Static Static translation consistently. maps an unregistered IP address of the same registered IP address on one to one basis. Static Nat is particular useful when a device needs to be assigned to the same address so it can accessed from outside the network such as a web servers and other devices.

You want to reduce collisions by creating separate collision domains and virtual LANs. Which of the following devices should you choose? Switch Router Active HUb bridge

Switch Use a switch to create additional collisions domain on a LAN. A switch filters an entire network and creates virtual LANS inside rather than dividing it into separate inter-networks as a router does. .

While viewing the status of the interfaces on a Cisco switch you see abnormally large number of over sized Ethernet frames being received on one interface. This interface is connected to a workstation located on the second floor. what could cause the problem to happen? An incorrect subnet mask has been configured on the workstation The workstation network board is jabbering.

The workstation network board is jabbering Frames that are too long are typically caused by faulty network card that jabber constantly sending garbage data.

What is the risk associated with smart technology used in networked devices such as smart refrigerators, environments controls or industrial equipment? They are vulnerable to exploits due to weaker security They are not physically secure, so they can be reconfigured by anyone who has access to them.

They are vulnerable to exploits due to weaker security

When configuring VLANS on a switch what type of switch ports are members of all VLANS defined on a switch? Gig and higher Ethernet Ports Uplink Ports Trunk ports

Trunk Ports A trunk port is a member of all VLANS defined on a switch and carries traffic between the switches

You mange a single subnet with three switches. The switches are connected to provide redundant paths better the switches? Spanning tree' Bonding Trunking

Trunking

You manage a network with two switches. The switches are connected together through their Gigabit Ethernet up link ports. You define VLAN 1 and VLAN 2 on each switch. A device on the first switch in VLAN 1 needs to communicate with a device on the second switch in VLAN 1. What should you configure to allow communication between these two devices through the switches. Layer 3 switching Bonding Trunking

Trunking A trunking prot is used to connect two switches together.

You would like to control the internt qaccess based on users,time, of day and websites visited. How can you do this? Enable windows firewall on each system. Add or remove exceptions to control access. Install a proxy server. Allow internet access only through the proxy server.

Use a proxy server