You are previewing Head First Networking.
O'Reilly logo
Head First Networking

Book Description

Frustrated with networking books so chock-full of acronyms thatyour brain goes into sleep mode? Head First Networking'sunique, visually rich format provides a task-based approach tocomputer networking that makes it easy to get your brain engaged.You'll learn the concepts by tying them to on-the-job tasks,blending practice and theory in a way that only Head Firstcan.With this book, you'll learn skills through a variety of genuinescenarios, from fixing a malfunctioning office network to planninga network for a high-technology haunted house. You'll learn exactlywhat you need to know, rather than a laundry list of acronyms anddiagrams. This book will help you:

  • Master the functionality, protocols, and packets that make upreal-world networking

  • Learn networking concepts through examples in the field

  • Tackle tasks such as planning and diagramming networks, runningcables, and configuring network devices such as routers andswitches

  • Monitor networks for performance and problems, and learntroubleshooting techniques

  • Practice what you've learned with nearly one hundred exercises,questions, sample problems, and projects

  • Head First's popular format is proven to stimulate learning andretention by engaging you with images, puzzles, stories, and more.Whether you're a network professional with a CCNA/CCNP or a studenttaking your first college networking course, Head FirstNetworking will help you become a network guru.

    Table of Contents

    1. Dedication
    2. Special Upgrade Offer
    3. Advance Praise for <span xmlns="" xmlns:epub="" xmlns:m="" xmlns:pls="" xmlns:ssml="" xmlns:svg="" class="emphasis"><em>Head First Networking</em></span>
    4. Praise for other <span xmlns="" xmlns:epub="" xmlns:m="" xmlns:pls="" xmlns:ssml="" xmlns:svg="" class="emphasis"><em>Head First</em></span> books books
    5. Authors of Head First Networking
    6. How to Use this Book: Intro
      1. Who is this book for?
        1. Who should probably back away from this book?
      2. We know what you’re thinking
      3. We know what your brain is thinking
      4. Metacognition: thinking about thinking
      5. Here’s what WE did:
      6. Here’s what YOU can do to bend your brain into submission
      7. Read Me
      8. The technical review team
      9. Acknowledgments
      10. Safari<sup xmlns="" xmlns:epub="" xmlns:m="" xmlns:pls="" xmlns:ssml="" xmlns:svg="">&#174;</sup> Books Online Books Online
    7. 1. Fixing Physical Networks: Walking on Wires
      1. Coconut Airways has a network problem
        1. The booking system network cable is busted
      2. How do we fix the cable?
        1. But how do we do this?
      3. Introducing the CAT-5 cable
      4. The CAT-5 cable dissected
        1. So why are the pairs twisted?
      5. So what’s with all the colors?
      6. Let’s fix the broken CAT-5 cable
      7. A closer look at the RJ-45 connector
        1. So which wire goes where?
      8. So what are the physical steps?
      9. You fixed the CAT-5 cable
      10. Coconut Airways has more than one network
      11. Introducing the coaxial cable
      12. Coaxial networks are bus networks
      13. So can we fix the cable?
      14. The network’s still not working
      15. So what goes on inside a coaxial cable?
        1. But what if there’s a break in the conductor?
      16. What about connectors and terminators?
      17. Use toner-tracer sets to listen to electrons
      18. No sound means no electrons
        1. So how do we find the continuity break?
      19. You’ve fixed the coaxial cable
      20. Introducing fiber-optic cables
        1. Fiber-optics have connectors too
      21. The Coconut Airways cable’s over-bent
        1. So what’s a fusion splicer?
      22. How to fix fiber-optics with a fusion splicer
      23. A fiber-optic connector needs fitting too
      24. We’re nearly ready to fix the connector
      25. There are two types of fiber
        1. Single mode fiber
        2. Multimode fiber
      26. Which mode fiber should you use?
      27. Let’s fit the connector on the fiber-optic
        1. So which technique should we use?
      28. Coconut Airways is sky high
    8. 2. Planning Network Layouts: Networking in the Dark
      1. Ghost Watch needs your help!
      2. Every good network needs a good plan
      3. So how does the device list help us plan a network?
      4. How to plan a network layout
      5. Let’s plan the cabling with a floorplan
      6. Ready to plot some network cables?
      7. So where have we got to?
      8. We need to decide on the cable management hardware
      9. Uh oh! The cabling is a mess
      10. Ghost Watch needs cable management hardware
      11. Things that go bump...
      12. You’ve really cleaned up that noise and straightened out <span xmlns="" xmlns:epub="" xmlns:m="" xmlns:pls="" xmlns:ssml="" xmlns:svg="" class="underline">MOST</span> of the cables! of the cables!
        1. What’s in the closet?
      13. Let’s start by labeling the cables
      14. But there are still lots of cables
        1. But what else can we do?
      15. So what’s a patch panel?
      16. Behind the scenes of a patch panel
      17. The wires go into a punch down block
      18. Roll the cameras!
    9. 3. Tools and Troubleshooting: Into the Wire
      1. Mighty Gumball won the Super Bowl contract
      2. A toner and tracer can check for a signal...
      3. ... but can’t check for signal quality
      4. Introducing the multimeter
        1. Use a multimeter to measure resistance
      5. So what’s resistance?
        1. When resistance is low
        2. When resistance is high
      6. So how well did the multimeter do?
      7. An oscilloscope shows voltage changes
      8. Voltage is really electrical pressure
        1. So how does this help us troubleshoot problems?
      9. Where does noise on network cables come from?
      10. So how well did the oscilloscope perform for Mighty Gumball?
      11. A logical analyzer uses voltage too
      12. When is a logical analyzer useful?
      13. So which tool is best?
      14. The Mighty Gumball bonus went to Jill
      15. A LAN analyzer combines the functions of all the other tools
      16. A LAN analyzer understands the network traffic in the signal
      17. So which tool is best?
      18. The Mighty Gumball problems are fixed!
    10. 4. Packet Analysis: You’ve Been Framed
      1. What’s the secret message?
        1. So how do we extract a message from a signal?
      2. Network cards handle encoding
        1. So how does the NIC encode the data?
      3. To get the message, reverse the encoding
        1. So how do we decode the signal?
      4. The Ethernet standard tells hardware how to encode the data
      5. A quick guide to binary
        1. So how do we convert a binary to decimal?
      6. Computers read numbers, humans read letters
        1. But isn’t there an easier way?
      7. Hexadecimal to the rescue
        1. So how do we convert a hexadecimal to decimal?
      8. We can convert to ASCII using hex
      9. Back at the spy agency...
      10. Protocols define the structure of a message
      11. Network frames have lots of layers
      12. Your friendly packet field guide
        1. UDP Packet - Protocol Type 17
        2. ICMP Packet - Protocol Type 1
        3. TCP Packet - Protocol Type 6
      13. So can we decode the secret message?
      14. We’ve got all the right packets... but not necessarily in the right order
      15. The packet tells you the correct order
    11. 5. Network Devices and Traffic: How Smart is Your Network?
      1. You’ve decoded the secret message...
        1. ...but how do we know who sent it?
      2. The packet information tells us where the packet came from
      3. So who’s the mole?
      4. There’s more to networks than computers
      5. Hubs don’t change the MAC address
        1. So which device sent the packet to the hub?
      6. A hub sends signals, and sends them <span xmlns="" xmlns:epub="" xmlns:m="" xmlns:pls="" xmlns:ssml="" xmlns:svg="" class="underline">everywhere</span>
        1. Hubs think in terms of electricity
      7. So what passed the signal to the hub?
      8. A switch sends frames, and only sends them where they need to go
        1. Switches think in terms of frames
      9. Switches store MAC addresses in a lookup table to keep the frames flowing smoothly
      10. The switch has the information...
      11. We can use software to monitor packets
      12. Let’s hook Wireshark up to the switch
      13. Wireshark gives us traffic information
      14. Routers have MAC addresses too
      15. We’re closing in!
      16. You’ve found the mole!
    12. 6. Connecting Networks with Routers: Bringing Things Together
      1. Networking <span xmlns="" xmlns:epub="" xmlns:m="" xmlns:pls="" xmlns:ssml="" xmlns:svg="" class="strikethrough">Walking</span> on the moon on the moon
      2. We need to connect two networks together
      3. The light’s on, but nobody’s home
        1. What do you think the flashing LEDs have to do with traffic on the network?
      4. Let’s see what traffic is on our network!
      5. MAC address versus IP address
      6. IP addresses give our networks a sense of location, and network nodes a sense of belonging to that location
      7. We retrieve IP addresses using the MAC address and the Address Resolution Protocol (ARP)
      8. So what’s the problem with the Moonbase?
      9. How do we get network traffic to move between networks?
      10. How the router moves data across networks
      11. Back to the Moonbase problem
      12. The secret of IP numbers is...
      13. Routers connect networks by doing the math...
      14. Back at the Moonbase...
      15. Are you ready to program the router?
      16. You just created this router config file!
      17. Let the router tell us what’s wrong...
    13. 7. Routing Protocols: It’s a Matter of Protocol
      1. Houston, we have a problem...
      2. Routing tables tell routers where to send packets
        1. We can see routes in the table using the show command
      3. Each line represents a different route
      4. So how do we enter routes?
      5. Routes help routers figure out where to send network traffic
      6. So are the moonbases now connected?
      7. Back on the moon...
        1. Moonbase 1 still has problems
      8. So how do we troubleshoot bad routes?
        1. We can start with the ping command
        2. So how does the ping command work?
      9. The traceroute command is useful too
      10. So what’s the problem with the network connection?
      11. The network address changes keep on coming...
      12. Use RIP to get routes to update themselves
        1. So what does this mean for Moonbase 1?
      13. So how do we set up RIP?
      14. But there’s still a problem...
      15. There are too many hops
      16. The routing protocol zoo
      17. So how do we setup EIGRP?
      18. We have lift off!
    14. 8. The Domain Name System: Names to Numbers
      1. The Head First Health Club needs a website
      2. Hello, my domain name is...
        1. So how do we get a domain name?
      3. Let’s go buy a domain name
      4. Uh-oh! We’re in trouble
        1. And she’s not the only one
      5. Introducing the DNS
      6. The DNS relies on name servers
      7. How the DNS sees your domain
      8. So how does this affect the Health Club?
      9. First install a DNS name server...
      10. ...then configure the name server
      11. The anatomy of a DNS zone file
      12. Here’s what the DNS zone file tells us about the Health Club servers
      13. The Health Club can’t send emails
      14. So what’s the problem?
      15. Email servers use RDNS to fight SPAM
      16. Check your sources with reverse DNS
      17. The dig command can do a reverse DNS lookup
      18. Your name server has another important zone file...
      19. The emails are working!
    15. 9. Monitoring and Troubleshooting: Listen to Your Network’s Troubles
      1. Pajama Death are back on tour
        1. So here’s your challenge...
      2. So where would you start troubleshooting a misfiring network?
      3. Start troubleshooting your network problems by checking in with your network devices
      4. Troubleshoot network connectivity with the ping command
        1. If you can ping, you get timings
        2. But what if you can’t ping?
      5. If the ping fails, check the cables
      6. Get started with the show interface command
        1. The interface’s network statistics are a gold mine of troubleshooting information
      7. The ticket network’s still not fixed
      8. SNMP to the rescue!
      9. SNMP is a network admininistrator’s communication tool
      10. How to configure SNMP on a Cisco device
      11. One hour to go...
      12. Get devices to send you their problems
      13. How to configure syslogd on a Cisco device
      14. How do you tell what’s in the logs?
        1. syslogd lets you fix problems before they’re problems
      15. Too much information can be just as bad as not enough
        1. What you need is <span xmlns="" xmlns:epub="" xmlns:m="" xmlns:pls="" xmlns:ssml="" xmlns:svg="" class="underline">relevant</span> information information
      16. How do you know which events are important?
      17. Pajama Death’s a sell-out!
    16. 10. Wireless Networking: Working Without Wires
      1. Your new gig at Starbuzz Coffee
        1. Starbuzz Coffee needs a wireless hotspot
      2. Wireless access points create networks using radio waves
      3. Let’s fit the wireless access point
      4. What about the network configuration?
      5. So what’s DHCP?
        1. DHCP allocates IP addresses
      6. First make sure the client has DHCP turned on...
      7. Second, make the wireless access point a DHCP server...
      8. ...and then specify an acceptable range of IP addresses
      9. So has setting up DHCP solved the problem?
      10. This time it’s personal
      11. We’ve run out of IP addresses
      12. NAT works by reallocating IP addresses
      13. So how do we configure NAT?
      14. So has this fixed the problem?
      15. There’s more than one wireless protocol
        1. Most newer access point support multiple protocols
        2. So is the Starbuzz wireless access point sorted?
      16. The central Starbuzz server needs to access the cash register
      17. Port mapping to the rescue!
        1. So port mapping is a bit like NAT in reverse
      18. Let’s set up port mapping on the Starbuzz access point
      19. The wireless access point is a success!
    17. 11. Network Security: Get Defensive
      1. The bad guys are everywhere
        1. The evil impersonator
        2. The evil attacker
      2. And it’s not just the NETWORK that gets hurt...
        1. The evil eavesdropper
      3. The big four in network security
      4. Defend your network against MAC address spoofing
      5. So how do we defend against MAC address spoofing?
      6. Defend your network against ARP poisoning attacks
      7. So what can we do about ARP poisoning attacks?
      8. It’s all about the access, baby!
        1. If an attacker can get past your router, then he’s on your network!
      9. Set up your router’s Access Control Lists to keep attackers out
      10. So how do we configure the Access Control List?
      11. Firewalls filter packets between networks
      12. Packet-filtering rules!
      13. Master the static packet filter
      14. Get smart with stateful packet-filters
      15. Humans are the weakest link in your security chain
      16. So how do social engineers operate?
      17. Smash social engineering with a clear and concise security policy
      18. You’ve hardened your network
    18. 12. Designing Networks: You Gotta Have a Plan!
      1. Now you have to plan a network from scratch!
      2. You have to know what the needs are before you can plan
      3. So you’ve developed your questions, now what?
      4. Look at your action plan
      5. So you have a physical layout, what’s next?
      6. Blueprints show everything in a building’s design
      7. You may have to modify your network design based on what you see in the blueprints!
      8. So you’ve got your physical network layout, what’s next?
        1. You have got several options to segment this into two networks
      9. Finally, you need an implementation plan
      10. Leaving town...
      11. It’s been great having you here in Networkville!
    19. A. Leftovers: The Top Ten Things (we didn’t cover)
      1. #1 Network topologies
        1. Star topology
        2. Bus topology
        3. Token Ring topology
      2. #2 Installing Wireshark
        1. Windows Install
        2. Mac OS X Install
        3. Linux Install (Ubuntu)
      3. #3 How to get to the console or terminal
        1. Windows
        2. Linux
        3. Mac OS X
      4. #4 The TCP Stack
      5. #5 VLANS
      6. #6 Cisco IOS Simulators
      7. #7 BGP
      8. #8 VPN
      9. #9 Intrusion Detection Systems
      10. #10 Cisco Certification
    20. B. Ascii Tables: Looking Things Up
      1. ASCII tables 0-31
      2. ASCII code tables 32-63
      3. ASCII code tables 64-95
      4. ASCII code tables 96-127
    21. C. Installing Bind: Getting a Server to talk DNS
      1. #1 Installing BIND on Windows (XP, 2000, Vista)
      2. #2 Installing BIND Mac OS X Server
      3. #3 Installing BIND Mac OS X Client & Linux
    22. Index
    23. About the Authors
    24. Special Upgrade Offer
    25. Copyright