Your Quick Reference Expert

CompTIA® Network+™ CertificationExam N10-005

What’s New?

Wireless network threatsIdentify the different types of security threats for wireless networks. See page 6.

Virtualization and cloud computingLearn how using virtual computers and the cloud can benefit your organization. See page 6.

Other Important Information

Cables, connectors, and Ethernet typesIdentify common cables and connectors, and review the various Ethernet architectures and designations. See page 2.

IP addresses (version 6)Learn about the five types of IPv6 addresses: link-local, site-local, global unicast, multicast, and anycast. See page 3.

Reference modelsIdentify the layers of the OSI and TCP/IP reference models and how they define network communications and control the flow of data. See page 3.

Ports and protocolsIdentify common TCP/IP protocols and the ports they use. See page 3.

Network devicesIdentify the functions of various network devices, such as repeaters, bridges, routers, and gateways. See page 5.

LAN installation componentsLearn the components required to install LAN wiring for a small network. See page 5.

TCP/IP and network troubleshootingUse TCP/IP and network troubleshooting tools to resolve communication issues. See page 6.

Network+ Certification informationFor current test objectives and certification information for the CompTIA Network+ Certification, visit www.comptia.org.

Get more help with Network+ topicsTo get more help with network applications, protocols, and security, visit the following Web sites:

y IEEE standards — www.ieee.org

y Certified Wireless Network Professional — www.cwnp.com

y Microsoft security — www.microsoft.com/security

y Cyber Security Tips — www.us-cert.gov/cas/tips

y CERT/CC advisories — www.cert.org/advisories/

LAN (local area network)A LAN is a specifically designed configuration of computers and other devices that are located within a confined area and connected by wires or radio waves that permit the devices to communicate with one another to share data and services.

y Node — A device with an address that can be accessed to send or receive information.

y Host — A computer with an operating system that manages its applications, its hardware, its network connection, and the resources that are shared on the network.

Large networks are frequently made up of segments and backbones.

y Segment — The portion of the network on either side of two network transmission devices. These devices include routers, bridges, repeaters, switches, and hubs.

y Backbone — A high-speed network link connecting segments. Backbones are used in large buildings or in networks that span more than one building.

Topologies

y Bus — All nodes are connected to a main communication line (bus)—typically a coaxial cable that is terminated at both ends. Transmissions from the nodes propagate the length of the medium and are received by all other nodes. In a bus topology, a malfunctioning node doesn’t disrupt the entire network. However, a break in the bus will disconnect hosts from each other.

y Ring — Nodes are arranged in a closed loop, with each node connected to a central device by two wires. The central device is called a multistation access unit (MSAU). Communication is enabled by passing a token around the ring; if a node has the token, it can transmit data. Repeaters at each node connection minimize signal degradation. Adding new nodes can be difficult, however, due to the closed ring.

y Star — Nodes are connected via point-to-point links to a central location (a hub or switch). This topology minimizes failure from an individual segment break and simplifies the adding or moving of nodes. One disadvantage: If the central node fails, the whole network becomes disconnected.

y Mesh — All nodes in the mesh have independent connections to all other nodes in the mesh. The mesh topology requires computers to have multiple network cards, and due to its complexity, it’s rarely used.

y Hybrid — Two or more different types of network topologies are combined into one network. For example, a combined bus and star design is shown above.

A

B

C

D

E

F

G

H

Bus

LAN Segment 1 Segment 2

Ring Star

MeshHybrid: Combined bus and star

Router Router

A BC

D E F

GH

GET T ING HELP

NETWORK+ CERT IF ICAT ION

MSAU

Backbone

Node HostNodeNodeNode Host NodeNodeNode

2Quick Reference

Ethernet architectures and designations

y 10-Mbps Ethernet (also called Twisted-Pair Ethernet or Ethernet IEEE 802.3) operates at a speed of 10 megabits per second (Mbps).

y 100-Mbps Ethernet (or Fast Ethernet) operates at a speed of 100 Mbps. It can also handle data at 10 Mbps, so devices running at the slower speed can operate on the same network.

y 1000-Mbps Ethernet (or Gigabit Ethernet) operates at a speed of 1000 Mbps (1 gigabit per second). It’s used for large, high-speed LANs and heavy-traffic server connections.

y 10 Gigabit Ethernet (or 10GbE) is the fastest of the current Ethernet standards, operating at a speed of 10 gigabits per second (Gbps).

Ethernet standard designations are based on the medium used:

y BASE-X and BASE-R standards — Run over fiber optic cable.

y BASE-W standards — Run over fiber optic cables; Ethernet frames are encapsulated in SONET frames.

y BASE-T standards — Run over twisted-pair cable, shielded or unshielded.

y BASE-CX standards — Run over shielded copper twisted-pair cable.

Medium and distance

STANDARD MEDIUM DISTANCE

Fast Ethernet standards

100BASE-TX Twisted-pair copper: CAT5 or above

100 meters per segment

100BASE-FX Single- or multi-mode optic fiber

400 meters for half-duplex

2 km for full-duplex over MMF

Gigabit Ethernet standards

1000BASE-T Unshielded twisted-pair: CAT5, CAT5e, or CAT6

100 meters per segment

1000BASE-CX Balanced copper shielded twisted-pair

25 meters

1000BASE-LX Single-mode optic fiber 5 km (minimum)

1000BASE-LX10 Single-mode optic fiber 10km

1000BASE-BX10 Single-mode fiber, over single-strand fiber

10km

1000BASE-SX Multi-mode optic fiber 500 meters

10 Gigabit Ethernet standards

10GBASE-T Copper twisted-pair: shielded or unshielded

100 meters with CAT6a; up to 55 meters with CAT6

10GBASE-SR

10GBASE-SW

Multi-mode optic fiber 26 or 82 meters, depending on cable type

300 meters over 50 microns at 2000 MHz/km with OM3 multi-mode fiber

10GBASE-LR 10GBASE-LW

Single-mode optic fiber 10 km

10GBASE-ER 10GBASE-EW

Single-mode optic fiber 40 km

Channel access methods

The channel access method determines the physical methodology by which data is sent across the media. The most common method is Carrier Sense Multiple Access with Collision Detection (CSMA/CD), which listens for transmissions from all nodes and repeats transmissions if data transfers fail due to multiple simultaneous transmissions, bad cabling, improper cable length, or improper termination.

In contrast, Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) warns nodes of impending transmissions to avoid collisions in the first place. CSMA/CA avoids the retransmission of lengthy data streams.

ETHERNET

y Coaxial — Either a 0.25"-thick cable (Thinnet, RG-58) that carries a signal up to 185 meters and has a 50-ohm impedance, or a 0.5"-thick cable (Thicknet, RG8 and RG-11) that carries a signal up to 500 meters.

y UTP (unshielded twisted-pair) — A type of twisted-pair wiring that carries a signal up to 100 meters. UTP cable does not have an insulating jacket, so it is susceptible to crosstalk.

y STP (shielded twisted-pair) — Twisted-pair wiring that carries a signal up to 100 meters. STP cable has a foil or braided jacket around the wiring to help reduce crosstalk and prevent electromagnetic interference.

y Fiber optic — A cable that carries light-pulse signals through a glass core at speeds ranging from 100 to 200,000 Mbps. There are two main types of fiber optic cable:

� SMF (single-mode fiber) — Has a core large enough to propagate only one light-pulse signal.

� MMF (multi-mode fiber) — Has a core large enough to propagate multiple light-pulse signals.

UTP and STP cabling standards

CATEGORY SPEED/FREQUENCY TYPICAL USE

CAT 5 100 Mbps; 100 MHz

155 Mbps ATM

Used for data and voice in Ethernet networks running at 10 or 100 Mbps.

CAT 5e 1000 Mbps; 200 MHz

155 Mbps ATM

Used for data and voice in Fast Ethernet and Gigabit Ethernet networks.

CAT 6 1000 Mbps; 250 MHz

155 Mbps ATM

Used for data in Fast Ethernet and Gigabit Ethernet networks.

CAT 6e 10 Gbps; 550 MHz Used in Gigabit Ethernet networks.

CAT 7 10 Gbps; 600 MHz Used for full-motion video and in government and manufacturing environments. Also known as ISO Class F.

Media connectors

y RJ-11 — A 4-wire connector used in North America to connect telephone equipment.

y RJ-45 — An 8-pin modular plug that is used to terminate UTP and STP cables. This connector can be used for both Ethernet and Token Ring applications.

y USB (Universal Serial Bus) — A universal connector that provides data transfer rates of up to 480 Mbps (USB 2.0).

y Direct cable connection with a null modem cable — A serial cable with RS-232 connectors on either end to enable direct two-way communication.

y IEEE 1394 (FireWire®) — A universal connector that supports Plug-and-Play installation and hot plugging. Provides data transfer rates of up to 400 Mbps and is often used for digital audio and video equipment.

y BNC — A 2-pin connector used to connect coaxial cables. Its twist-lock mechanism prevents cable disconnections.

y FC (fiber connector) — A threaded optical connector that uses a special curved polish on the connector. Good for SMF or MMF.

y ST (straight tip) — A frequently used fiber optic connector. It is a keyed, BNC-style connector.

y SC (subscriber connector) — An international standard push-pull fiber optic connector. The SC connector has both transmit and receive fibers in a single clip.

y LC (local connector) — A small-form-factor connector based on the RJ-45 interface; suited for high-density applications.

CABLES AND CONNECTORS

3

A reference model is a layered architecture that outlines how communica-tions should occur within and between networks. Each layer is responsible for one aspect of communication. Within a system, a layer can communicate only with the layer immediately above or immediately below itself. Between systems, a layer can communicate only with the same layer in another system.

The two main models are the OSI (Open System Interconnection) model and the TCP/IP model.

The OSI model

LAYER FUNCTION

Application Allows applications to use the network. Handles network access, flow control, and error recovery.

Presentation Translates data into a form that’s usable by the Application layer. Responsible for protocol conversion, data translation and encryption, and data compression management.

Session Establishes, maintains, and manages communication sessions between computers.

Transport Provides reliable transmission of data segments.

Network Ensures that information arrives at its intended destination. Responsible for addressing, transport routes, routing, packet switching, message handling, and network traffic management.

Data Link Deals with the links and mechanisms to move data. Topology (Ethernet or Token Ring) is defined here. Contains two sublayers: MAC and LLC.

Physical Transmits data over a physical medium. Specifies cabling, cards, and other aspects of establishing a physical link between computers.

The TCP/IP model

LAYER OSI EQUIVALENT LAYERS PROTOCOLS

Application Session, Presentation, and Application

SMTP, FTP, Telnet, SNMP, DNS, and NFS

Transport Transport TCP and UDP

Internet Network IP and ICMP

Network Interface

Physical and Data Link 802.3, 802.5, 802.11, 802.15, coaxial, and fiber optic

Protocols for the Transport and Network/Internet layers

y TCP (Transmission Control Protocol) runs at the Transport layer and provides connection-oriented services. TCP provides guaranteed delivery, proper sequencing, and data integrity checks.

y UDP (User Datagram Protocol) runs at the Transport layer and provides connectionless, unacknowledged communications.

y IP (Internet Protocol) runs at the OSI Network or TCP/IP Internet layer and provides connectionless services. IP provides packet routing and delivery between computer systems, without guaranteeing proper sequencing or even arrival at the destination.

REFERENCE MODELS

IP addresses, version 4 (IPv4)

These 32-bit addresses are written as four octets or bytes, separated by periods as follows: 208.206.88.56.

CLASS OPENING BITS

DEFAULT SUBNET MASK NETWORK RANGE

A 0 255.0.0.0 1.0.0.0–126.0.0.0

B 10 255.255.0.0 128.0.0.0–191.255.0.0

C 110 255.255.255.0 192.0.0.0–223.255.255.0

D 1110 N/A 224.0.0.0–239.0.0.0

E 1111 N/A 240.0.0.0–255.0.0.0

IP addresses, version 6 (IPv6)

These 128-bit address are written as eight bytes, separated by colons as follows: 0:0:0:0:128:34:52:7. With IPv6, there are five types of addresses:

y Link-local — Similar to IPv4’s APIPA. Link-local addresses are self assigned, using the Neighbor Discovery process. Link-local addresses start with fe80::.

y Site-local — Similar to an IPv4 private address. Site-local addresses begin with fe and use c to f for the third hexadecimal digit.

y Global unicast — Similar to an IPv4 public address. A global unicast address is identified for a single interface. Global unicast addresses are routable and reachable on the IPv6 Internet. All IPv6 addresses that start with the binary values 001 (2000::/3) through 111 (e000::/3) are global addresses, except for ff00::/8, which are reserved for multicasts.

y Multicast — An address that identifies a multicast group. As with IPv4, an IPv6 multicast sends information or services to all members of a multicast group. If the first 16 bits of an IPv6 address are ff00, it’s a multicast address.

y Anycast — A new type of address in IPv6. Anycast addresses identify a group of interfaces, typically on separate nodes. Packets sent to an anycast address are delivered to the nearest interface as identified by the routing protocol’s distance measurement.

DHCP and DHCPv6

Dynamic Host Configuration Protocol (DHCP) is an automated mechanism for assigning IP addresses to clients. A computer configured to obtain its IP configuration through DHCP or DHCPv6 will contact a DHCP or DHCPv6 server on the local network and get the needed information from it.

IP ADDRESSING

PROTOCOL PORTS FUNCTION

FTP 20, 21 Supports uploading and downloading files and requesting directory listings from remote servers.

SSH 22 Exchanges data between two network nodes over a secure channel. A secure replacement for Telnet.

SMTP 25 Provides a mechanism for the transfer of e-mail information between systems.

DNS 53 Provides a common naming convention throughout the Internet.

HTTP

HTTPS

80

443

Provides the framework for exchanging text, images, sound, and video on the Web. HTTPS runs over Secure Sockets Layer (SSL).

IMAP 143 Common protocol used to retrieve e-mail messages. IMAP4’s capabilities are beyond those of POP3.

DHCP 67, 68 Dynamically assigns IP addresses to network devices.

SNMP 161 Provides a way to send management information between TCP/IP hosts.

COMMON PROTOCOLS AND PORTS

7 Application

6 Presentation

5 Session

4 Transport

3 Network

1 Physical

2 Data Link MACLLC

OSI model

4 Application

3 Transport

2 Internet

1 Network Interface

TCP/IP model

4Basic Topics

Wireless LAN (WLAN) technology uses radio waves or infrared light instead of cables to connect network nodes. Connections are made with a wireless NIC, which includes an antenna to send and receive signals. Wireless devices can communicate directly (for example, via an infrared connection), or they can connect to a LAN by way of a wireless access point (WAP).

Wireless communication standards

STANDARD SPEED AND FREQUENCY INDOOR DISTANCE

802.11a Up to 54 Mbps at 5 GHz Up to 35 meters

802.11b Up to 11 Mbps at 2.4 GHz Up to 35 meters

802.11g 20+ Mbps at 2.4 GHz Up to 35 meters

802.11n Up to 300 Mbps at either 5 GHz or 2.4 GHz

Up to 70 meters

Wireless network protocols

y Wi-Fi (Wireless Fidelity) — The most widely used wireless technology at present. IEEE wireless standards 802.11b and 802.11g are collectively referred to as Wi-Fi.

y 802.11a — An improved version of the original Wi-Fi technology, based on the same IEEE 802 standard. Devices supporting 802.11a aren’t compatible with 802.11b.

y Bluetooth — A short-range wireless technology. Its limited transmission distance (10 meters) generally confines it to connecting nodes in a single room or adjacent rooms. Newer devices have a higher transmitting power that increases the range to 100 meters.

y WiMax (IEEE 802.16 Air Interface Standard) — A point-to-multipoint broadband wireless access standard.

Wireless LAN security protocols

y WEP (Wired Equivalent Privacy) — A security protocol for wireless LANs specified by 802.11. WEP uses encryption to protect the vulnerable link between clients and access points.

y WPA (Wi-Fi Protected Access) — A specification that replaces WEP’s keying mechanism with a more robust system called Temporal Key Integrity Protocol. WPA also adds a strong message-integrity check and allows for authentication using 802.1X.

y WPA2— A specification that builds on WPA by adding more features from the 802.11i standard. Notably, WPA2 uses the Advanced Encryption System (AES) cipher for stronger encryption.

y 802.11i — An authentication standard for wired and wireless LANs, used to identify users before allowing their traffic onto the network. It can be used in wireless environments to authenticate users for more secure WEP, Wi-Fi Protected Access, or 802.11i deployments.

WIRELESS LANS

Firewalls

A firewall is hardware or software that controls traffic between networks, typically between a public network and a private internal network. Firewalls examine the contents of network traffic and permit or block transmission based on rules. Types of firewalls include:

y Packet filter — A mechanism for filtering out datagrams that don’t meet specified security criteria as the datagrams pass through a router.

y Bastion host — A heavily fortified network server through which all external traffic must pass.

y Proxy server — A server that protects the IP addresses of internal hosts by presenting its own IP address to external sites instead.

Security zones y Extranet, Internet, or public network — A network area that sits

unprotected in front of a firewall.

y Intranet or private network — A network area behind a firewall.

y DMZ — A network area between the private network (intranet) and a public network (extranet).

Hardening your OS or NOS

Modify the default configuration of your operating system (OS) or network operating system (NOS) to make it more secure from outside threats.

y Identify and remove unused applications and services that, if compromised, could reveal sensitive information about a system.

y Remove unused or unnecessary file shares.

y Implement and enforce strong password policies. Remove or disable all expired or unneeded accounts, and change default device passwords.

y Limit the number of administrator accounts available. Set privileges so that resources are accessible only on an as-needed basis.

y Set account lockout policies to discourage password cracking.

y Apply the latest firmware and software updates and hot fixes.

y Back up the system on a periodic basis in case of emergency.

y Log all user account and administrative activity so you can conduct a forensic analysis if the system is compromised.

y Monitor physical and virtual access to your network and devices.

IDSs and IPSsIntrusion detection systems (IDSs) are monitoring devices that help you identify attacks in progress and conduct forensic analysis after an attack. Many IDSs look for known patterns or signatures to aid in detecting attacks. There are two types of IDSs:

y Network intrusion detection system (NIDS) — Uses dedicated network devices or servers (sensors) to monitor traffic volumes on one or more network segments or on a network entry point, such as a firewall.

y Host intrusion detection system (HIDS) — Uses software agents to detect and track computer-related activity. A HIDS monitors operating system files for unauthorized changes and watches for unusual usage patterns or failed logon requests. Host-based IDS solutions don’t scale well across enterprises with a large number of computers.

An intrusion prevention system (IPS) takes the IDS functions one step further. It can actually shut down suspicious traffic by terminating the network connection or user session or by blocking access to the targeted host, service, or application.

Virtual private networks (VPNs)A VPN uses a public infrastructure to provide remote offices or users with secure access to the company’s network. VPNs typically use Internet Protocol Security (IPSec) for encrypting data traveling across a public network. IPSec enables two types of encryption:

y Transport encryption — The underlying data in a packet is encrypted and placed within a new packet on the public network.

y Tunnel encryption — The entire packet, including its header, is encrypted and then placed in the public network’s packet.

With IPSec in place, a VPN can virtually eliminate packet sniffing and identity spoofing.

SECURIT Y PRACT ICES AND DEVICES

CERTBLASTER® PRACTICE TEST

The purchase of this CourseCard entitles you to one copy of the CertBlaster® test preparation software for the CompTIA Network+ N10-005 Certification exam. To help you pass your exam, CertBlaster provides hundreds of practice questions, exam simulations containing the same number of questions as an actual exam, and a personalized study path.

To install your CertBlaster:

1. Go to http://www.axzopress.com.

2. Under Downloads, click CertBlaster.

3. Click the link for CompTIA Network+ N10-005.

4. Save the .EXE file to your hard drive.

5. Double-click the .EXE file.

6. Click OK and follow the on-screen instructions.

7. When prompted for a password, enter c_net+005.

5Advanced Topics

DEVICE OSI LAYER FUNCTION

Repeater Physical Boosts the electronic signal from one network cable segment and passes it to another.

Hub Physical Takes the signal transmitted from one computer and propagates it to all other computers on the network.

Wireless access point (WAP)

Physical Acts as a central transmitter and receiver of WLAN radio signals; allows WLANs to join a wired network.

Multistation access unit (MSAU)

Physical Connects the nodes in a Token Ring network. Each node is connected to the MSAU by two wires. Communication is enabled by passing a token around the ring to each node—if a node has the token, it can transmit data.

Network interface card (NIC)

Data Link Provides a communication channel between your computer’s motherboard and the network.

Bridge Data Link Connects two LANs and makes them appear to be one; or segments a larger LAN into two smaller pieces.

Switch Data Link Takes an incoming packet of data, looks inside at the destination hardware address, and then sends the packet out the port that’s connected to the destination machine.

Multilayer switch

Data Link up to Application

Combines data switching with routing by using an application-specific integrated circuit (ASIC). Some switches can implement data switching up to the Application layer.

Brouter Data Link and Network Interface

Acts as a router for routable protocols, and as a bridge for non-routable protocols.

Router Network Interface

Connects two networks and determines the best path for forwarding data packets from one network to the next.

Gateway Any layer Provides links between mixed environments (such as PC-based LANs) and host environments (such as SNAs).

NETWORK DEVICES

Network access point (NAP)

A NAP is a major Internet connection point that’s used to connect and route traffic between smaller commercial backbones.

Internet service provider (ISP)

An ISP is a business that provides connectivity to the Internet. Individual customers connect to the ISP via cable lines, DSL, or POTS. These lines are consolidated at a terminal server, which then connects to the ISP’s LAN. This LAN is connected to servers that provide various services, such as e-mail and Web hosting, to customers.

For a smaller ISP, a router connects its LAN via a T1 line to a regional ISP’s network. Before data is moved onto the T1 line, a CSU/DSU (Channel Service Unit/Digital Service Unit) cleans and formats the data.

For a regional ISP, a router connects the LAN directly to the Internet backbone.

LAN installation components y Demarcation point (demarc) — The point

at which the communications network owned by one company connects to the communications network owned by another company. For most companies, the demarc is the point at which their network connects to the cabling owned by the ISP.

y Demarc terminating device — The device, located at the demarc, that handles code and protocol conversions. It also handles the buffering required for communications between an ISP and your internal network.

y Demarc extension — Cabling and a port; needed if the demarc isn’t in the same location as the main cross-connect. The extension is typically installed by the ISP.

y Main cross-connect — The location where signals are distributed from the internal network to the demarc.

y Main distribution frame (MDF) — A network rack that holds the devices used to manage the connections between external communication cables and the cables of your internal network.

y Intermediate cross-connects — Cross-connects on each floor that are connected to the main cross-connect through network backbone cabling. They are sometimes called vertical cabling.

y Intermediate distribution frames (IDFs) — Network racks that hold the devices connecting each floor’s internal wiring to the MDF.

y Workstation drops — Horizontal cables that are run—without splice points, cable junctures, or taps—from the telecommunications room on each floor to each individual workstation.

y Horizontal cross-connect — The junction point for the workstation cables on each floor.

Typical UTP installation

The TIA/EIA-568-C standard specifies UTP standards for workstation runs. Typically, a patch cable (also called a user cable) runs from the node’s network card to the RJ-45 wall jack. Then, drop cables run from the RJ-45 wall jacks to a termination block in the telecommunications room. The total length of the drop, including patch and equipment cables, can’t exceed the total maximum cable length for the chosen media.

Telecommunications room

The telecommunications room is where network wiring is terminated. You can choose either of the following termination methods:

y Direct patch panel termination — Terminates wiring directly into a patch panel. Most often found in Cat 5e or Cat 6 installations.

y Punchdown termination with cross-connect wiring — Uses a punchdown block to terminate station cables and cross-connect the cables to other punchdown locations. There are two types of punchdown blocks:

� 110 block — Has two components. A 110 wiring block holds wires in place, and a 110C connecting block electronically terminates cables.

� 66M block (older technology) — Terminates a 25-pair phone trunk cable in a wiring closet; then individual 4-pair wires go from there to the user’s desk.

NETWORK-TO-NETWORK CONNECT IONS

TECHNOLOGY SPEED DESCRIPTION

Digital Subscriber Line (DSL)

Up to 1.5 Mbps Uses a digital modem to make high-speed connections through regular, analog phone lines.

Cable 512 Kbps to 5 Mbps

Uses the same lines that carry cable television signals.

Satellite Up to 1.5 Mbps Uses a dish to make connections by sending and receiving signals from satellites in orbit around the earth.

Wireless Up to 10 Mbps Uses signals sent over radio waves to transmit data between devices.

WiMax Up to 70 Mbps Wireless technology that can be deployed in areas where physical limitations prevent broadband access.

Cellular Faster than dial-up, but slower than DSL or cable

Uses an Internet-capable device with a cellular network PC card to connect to the Internet by using one of the following connection technologies: EDGE, EVDO, or HSDPA.

T1 1.544 Mbps Provides digital communications through a dedicated leased line provided through a common carrier.

WIDE AREA NETWORK (WAN) CONNECT IONS

Floor 3

Floor 2

Floor 1

IDF

IDF

MDF Demarc

Backbone

6

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6Top Productivity Tips and Solutions

Be methodical in your troubleshooting

1. Identify the problem.

2. Establish a theory of probable cause.

3. Test the theory to determine the cause.

4. Establish a plan of action to resolve the problem, and identify potential effects.

5. Implement a solution or escalate the problem as necessary.

6. Verify full system functionality and implement preventative measures.

7. Document findings, actions, and outcomes.

Use these TCP/IP troubleshooting tools

COMMAND USED TO…

Tracert Determine the route that a packet took to reach its destination.

Ping Verify connections to a remote host, or test the local TCP/IP installation if the loopback address is used. Works by sending ICMP echo packets.

Arp Gather hardware addresses of local hosts and the default gateway.

Netstat Display protocol statistics and get information about TCP/IP connections.

Nbstat Display statistics and connections for NetBIOS over TCP/IP, including DNS and WINS name resolution, local cache lookup, and LMHOSTS and HOSTS file information.

IPConfig Display IP addressing information for the local network adapter(s) or a specified NIC.

NSLookup Query a name server and find out which name resolves to which IP address.

Route Allows you to manually control network routing tables.

Use these networking tools

TOOL USED TO…

Cable stripper Remove the outer insulation from network cables and expose the wires inside them.

Snips Cut or trim cables.

Punchdown tool Connect wires to a punchdown block.

Crimper Attach a connector to a network cable. Crimpers come in varieties for RJ-11, RJ-45, and coaxial cables.

Butt set Test and verify telephone lines.

Time-domain reflectometer (TDR)

Locate problems or breaks in metallic wires, such as coaxial cable and twisted-pair network cables.

Optical TDR (OTDR) Locate faults in optical fiber.

Certifier Test and verify network cable speeds by sending data packets across the network.

Temperature monitor Monitor temperature in various environments, especially in rooms that contain networking devices.

Voltage event recorder

Measure electrical properties to determine the level and quality of the power supply.

Network analyzer Identify problems with cabling, jacks, network cards, hubs, and TCP/IP. Network analyzers are portable devices.

Watch for security threats and attacks

y Denial-of-service (DoS) attack — An attack that consumes or disables resources in order to interrupt services to legitimate users. A distributed denial-of-service (DDoS) uses multiple devices to launch the attack.

y Viruses — Malicious software that spreads from system to system by attaching itself to data or other files.

y Worms — Malicious software that exploits networking vulnerabilities with the intent of propagating itself.

y Man-in-the-middle attack — An attack in which the attacker listens in on a session between two communicating hosts. Wireless systems are very vulnerable to this type of attack.

y Smurf attack — A non-OS-specific attack that uses a third party’s network segment to overwhelm a host with a flood of Internet Control Message Protocol (ICMP) packets.

y Buffer overflow — An attack in which malicious code fills a computer’s buffer, causing it to overflow into other memory areas, overwriting legitimate data.

y Social engineering — The act of exploiting someone’s trust in order to get information that the attacker can then use to gain access to a computer system.

Wireless threats

y War driving — This is the practice of scanning for open wireless access points by using a laptop or other device.

y War chalking — This is the process of marking buildings, curbs, and other landmarks to indicate the presence of an available access point and its connection details.

y WEP/WPA cracking — Because of WEP’s inherent vulnerability, WEP keys are easy to crack with readily available software. Although WPA is more secure, it can also be cracked using software that’s not difficult to obtain.

y Evil twin — An attacker sets up a rogue access point to eavesdrop on wireless communication at a public hotspot or on a home or business network. Users give away usernames and passwords, thinking that they’re logging onto a valid AP.

Threat mitigation

y Install the latest security updates and antivirus signature files.

y Create an incident-response policy.

y Implement security policies and train users.

NETWORK SECURIT YTROUBLESHOOT ING

Virtualization enables you to run multiple simulated computers, called virtual machines, on a single physical computer, the host. Virtualization can reduce your application licensing and hardware costs.

Cloud computing lowers your operating costs by providing dynamic services, typically offered by third-party companies, over the Internet. Services include:

y Software as a Service (SaaS) — Applications, such as the Google Apps suite of office applications and Microsoft’s Office Web Apps.

y Platform as a Service (PaaS) — Server systems, such as database and e-mail servers.

y Infrastructure as a Service (IaaS) — Fully configured equipment.

y Network as a Service (NaaS) — Network-based services, such as monitoring and Quality of Service management.

VIRTUALIZAT ION AND THE CLOUD

9 781426 033964

ISBN-10 1-4260-3396-6ISBN-13 978-1-4260-3396-4

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