Networking Flashcards
What does TCP/IP stand for?
Transmission Control Protocol/Internet Protocol
What is TCP?
Transmission Control Protocol
Connection-oriented
– A formal connection setup and close
- “Reliable” delivery
– Recovery from errors
– Can manage out-of-order messages or retransmissions - Flow control
– The receiver can manage how much data is sent
What is UDP?
User Datagram Protocol
* Connectionless - No formal open/close to the connection
- “Unreliable” delivery
– No error recovery
– No reordering of data or retransmissions - No flow control
– Sender determines the amount of data transmitted
When would you use UDP?
Real-time communication
– There’s no way to stop and resend the data
– Time doesn’t stop for your network
Connectionless protocols
– DHCP (Dynamic Host Configuration Protocol)
– TFTP (Trivial File Transfer Protocol)
What does DHCP stand for?
Dynamic Host Configuration Protocol
What does TFTP stand for?
TFTP (Trivial File Transfer Protocol)
When would you use TCP? (and with what?)
- Connection-oriented protocols prefer a “return receipt”
– HTTPS (Hypertext Transfer Protocol Secure)
– SSH (Secure Shell) - The application doesn’t worry about out of order
frames or missing data
– TCP handles all of the communication overhead
– The application has one job
What are Non-ephemeral ports ?
permanent port numbers
– Ports 0 through 1,023
– Usually on a server or service
What are ephemeral ports ?
- Ephemeral ports – temporary port numbers
– Ports 1,024 through 65,535
– Determined in real-time by the client
Port numbers range
TCP and UDP ports can be any number between
0 and 65,535
* Most servers (services) use non-ephemeral
(not-temporary) port numbers
– This isn’t always the case
– It’s just a number.
T or F – TCP port numbers aren’t the same as UDP port number
T
T or F - TCP and UDP are encapsulated within IP.
T
What is SSH?
SSH - Secure Shell
* Encrypted communication link in terminal communication between systems
What are Routers?
Routes traffic between IP subnets
– Makes forwarding decisions based on IP address
– Routers inside of switches sometimes called
“layer 3 switches”
* Often connects diverse network types
– LAN, WAN, copper, fiber
What are Switches?
- Bridging done in hardware
– Application-specific integrated circuit (ASIC)
– Forwards traffic based on data link address - Many ports and features
– The core of an enterprise network
– May provide Power over Ethernet (PoE) - Multilayer switch
– Includes routing functionality
What are Unmanaged Switches?
- Very few configuration options
– Plug and play - Fixed configuration
– No VLANs - Very little integration with other devices
– No management protocols - Low price point
– Simple is less expensive
What are managed Switches?
- VLAN support
– Interconnect with other switches via 802.1Q - Traffic prioritization
– Voice traffic gets a higher priority - Redundancy support
– Spanning Tree Protocol (STP) - Port mirroring
– Capture packets - External management
– Simple Network Management Protocol (SNMP)
What are Access points?
Not a wireless router
– A wireless router is a router and an access point
in a single device
* An access point is a bridge
– Extends the wired network onto the wireless network
– Makes forwarding decisions based on MAC address
What are Patch Panels?
Combination of punch-down blocks and
RJ-45 connectors
* Runs from desks are made once
– Permanently punched down to patch panel
* Patch panel to switch can be easily changed
– No special tools
– Use existing cables
What are Firewalls?
- Filters traffic by port number
– OSI layer 4 (TCP/UDP)
– Some firewalls can filter based on the application - Can encrypt traffic into/out of the network
– Protect your traffic between sites - Can proxy traffic
– A common security technique - Most firewalls can be layer 3 devices (routers)
– Usually sits on the ingress/egress of the network
What is Power over Ethernet (PoE)?
Power provided on an Ethernet cable
– One wire for both network and electricity
– Phones, cameras, wireless access points
– Useful in difficult-to-power areas
* Power provided at the switch
– Built-in power - Endspans
– In-line power injector - Midspans
What is PoE switch?
- Power over Ethernet
– Commonly marked on the switch or interfaces
Explain PoE, PoE+, PoE++
- PoE: IEEE 802.3af-2003
– The original PoE specification
– Now part of the 802.3 standard
– 15.4 watts DC power, 350 mA max current - PoE+: IEEE 802.3at-2009
– Now also part of the 802.3 standard
– 25.5 watts DC power, 600 mA max current - PoE++: IEEE 802.3bt-2018
– 51 W (Type 3), 600 mA max current
– 71.3 W (Type 4), 960 mA max current
– PoE with 10GBASE-T
Explain Hub
- “Multi-port repeater”
– Traffic going in one port is repeated to
every other port - Everything is half-duplex
- Becomes less efficient as network traffic increases
- 10 megabit / 100 megabit
- Difficult to find today
Explain Cable modem
- Broadband
– Transmission across multiple frequencies
– Different traffic types - Data on the “cable” network
– DOCSIS (Data Over Cable Service Interface Specification) - High-speed networking
– Speeds up to 1 Gigabit/s are available - Multiple services
– Data, voice, video
Explain DSL modem
- ADSL (Asymmetric Digital Subscriber Line)
– Uses telephone lines - Download speed is faster than the upload
speed (asymmetric)
– ~10,000 foot limitation from the central office (CO)
– 52 Mbit/s downstream / 16 Mbit/s upstream are
common
– Faster speeds may be possible if closer to the CO
Explain ONT
Optical network terminal
– Fiber to the premises
* Connect the ISP fiber network to the copper network
– Demarcation point (demarc) in the data center
– Terminal box on the side of the building
* Line of responsibility
– One side of the box is the ISP
– Other side of the box is your network
Explain NIC
Network Interface Card (NIC)
* The fundamental network device
– Every device on the network has a NIC
– Computers, servers, printers, routers, switches,
phones, tablets, cameras, etc.
* Specific to the network type
– Ethernet, WAN, wireless, etc.
* Often built-in to the motherboard
– Or added as an expansion card
* Many options - Single port, multi-port, copper, fiber
Explain SDN
SDN (Software Defined Networking)
* Networking devices have different functional
planes of operation
– Data, control, and management planes
* Split the functions into separate logical units
– Extend the functionality and management
of a single device
– Perfectly built for the cloud
* Infrastructure layer / Data plane
– Process the network frames and packets
– Forwarding, trunking, encrypting, NAT
* Control layer / Control plane
– Manages the actions of the data plane
– Routing tables, session tables, NAT tables
– Dynamic routing protocol updates
Application layer / Management plane
– Configure and manage the device
– SSH, browser, API
Explain Wireless standards 802.11a
- One of the original 802.11 wireless standards
– October 1999 - Operates in the 5 GHz range
– Or other frequencies with special licensing - 54 megabits per second (Mbit/s)
- Smaller range than 802.11b
– Higher frequency is absorbed by objects in the way - Not commonly seen today
Explain Wireless standards 802.11b
- Also an original 802.11 standard - October 1999
- Operates in the 2.4 GHz range
- 11 megabits per second (Mbit/s)
- Better range than 802.11a, less absorption problems
- More frequency conflict
– Baby monitors, cordless phones,
microwave ovens, Bluetooth - Not commonly seen today
Explain Wireless standards 802.11g
- An “upgrade” to 802.11b - June 2003
- Operates in the 2.4 GHz range
- 54 megabits per second (Mbit/s) - Similar to 802.11a
- Backwards-compatible with 802.11b
- Same 2.4 GHz frequency conflict problems as 802.11b
Explain Wireless standards 802.11n
802.11n (Wi-Fi 4)
* The update to 802.11g, 802.11b, and 802.11a
– October 2009
* Operates at 5 GHz and/or 2.4 GHz
– 40 MHz channel widths
* 600 megabits per second (Mbit/s)
– 40 MHz mode and 4 antennas
* 802.11n uses MIMO
– Multiple-input multiple-output
– Multiple transmit and receive antennas
Explain Wireless standards 802.11ac
802.11ac (Wi-Fi 5)
* Approved in January 2014
– Significant improvements over 802.11n
* Operates in the 5 GHz band
– Less crowded, more frequencies (up to 160 MHz
channel bandwidth)
* Increased channel bonding - Larger bandwidth usage
* Denser signaling modulation
– Faster data transfers
* Eight MU-MIMO downlink streams
– Twice as many streams as 802.11n
– Nearly 7 gigabits per second
Explain Wireless standards 802.11ax
802.11ax (Wi-Fi 6)
* Approved in February 2021
– The successor to 802.11ac/Wi-Fi 5
* Operates at 5 GHz and/or 2.4 GHz
– 20, 40, 80, and 160 MHz channel widths
* 1,201 megabits per second per channel
– A relatively small increase in throughput
– Eight bi-directional MU-MIMO streams
* Orthogonal frequency-division multiple access (OFDMA)
– Works similar to cellular communication
– Improves high-density installations
Explain RFID
RFID (Radio-frequency identification)
* It’s everywhere
– Access badges
– Inventory/Assembly line tracking
– Pet/Animal identification
– Anything that needs to be tracked
* Radar technology
– Radio energy transmitted to the tag
– RF powers the tag, ID is transmitted back
– Bidirectional communication
– Some tag formats can be active/powered
Explain NFC
NFC (Near field communication)
* Two-way wireless communication
– Builds on RFID, which is mostly one-way
* Payment systems
– Major credit cards, online wallets
* Bootstrap for other wireless
– NFC helps with Bluetooth pairing
* Access token, identity “card”
– Short range with encryption support
802.11 technologies (big picture)
- Frequency
– 2.4 GHz or 5 GHz
– And sometimes both - Channels
– Groups of frequencies, numbered by the IEEE
– Non-overlapping channels would be ideal - Regulations
– Most countries have regulations to
manage frequency use
– Spectrum use, power output,
interference requirements, etc.
bluetooth technologies (big picture)
- Remove the wires
– Headsets, speakers, keyboards / mice - Uses the 2.4 GHz range
– Unlicensed ISM
(Industrial, Scientific and Medical) band
– Same as 802.11 - Short-range
– Most consumer devices operate
to about 10 meters
– Industrial Bluetooth devices can communicate
over 100 meters
what is DNS server
Domain Name System
– Convert names to IP addresses
– And vice versa
* Distributed naming system
– The load is balanced across many different servers
* Usually managed by the ISP or IT department
– A critical resource
what is DHCP server
DHCP server
* Dynamic Host Configuration Protocol
– Automatic IP address configuration
* Very common service
– Available on most home routers
* Enterprise DHCP will be redundant
– Usually running on central servers
what is File server
File server
* Centralized storage of documents,spreadsheets,
videos, pictures, and any other files
– A fileshare
* Standard system of file management
– SMB (Server Message Block),
Apple Filing Protocol (AFP), etc.
* The front-end hides the protocol
– Copy, delete, rename, etc.
what is Print server
Print server
* Connect a printer to the network
– Provide printing services for all network devices
* May be software in a computer
– Computer is connected to the printer
* May be built-in to the printer
– Network adapter and software
* Uses standard printing protocols
– SMB (Server Message Block), IPP (Internet
Printing Protocol), LPD (Line Printer Daemon)
what is Print server
Print server
* Connect a printer to the network
– Provide printing services for all network devices
* May be software in a computer
– Computer is connected to the printer
* May be built-in to the printer
– Network adapter and software
* Uses standard printing protocols
– SMB (Server Message Block), IPP (Internet
Printing Protocol), LPD (Line Printer Daemon)
what is Mail server
Mail server
* Store your incoming mail
– Send your outgoing mail
* Usually managed by the ISP or the IT department
– A complex set of requirements
* Usually one of the most important services
– 24 x 7 support
what is Syslog
Syslog
* Standard for message logging
– Diverse systems, consolidated log
* Usually a central logging receiver
– Integrated into the SIEM
* You’re going to need a lot of disk space
– No, more. More than that.
what is Web server
Web server
* Respond to browser requests
– Using standard web browsing protocols - HTTP/HTTPS
– Pages are built with HTML, HTML5
* Web pages are stored on the server
– Downloaded to the browser
– Static pages or built dynamically in real-time
what is Authentication server
- Login authentication to resources
– Centralized management - Almost always an enterprise service
– Not required on a home network - Usually a set of redundant servers
– Always available
– Extremely important service
what is Spam
- Unsolicited messages
– Email, forums, etc. - Various content
– Commercial advertising
– Non-commercial proselytizing
– Phishing attempts - Significant technology issue
– Security concerns, resource utilization,
storage costs, managing the spam
what is Spam gateways
- Unsolicited email
– Stop it at the gateway before it reaches the user
– On-site or cloud-based
what is All-in-one security appliance
- Next-generation firewall, Unified Threat
Management (UTM) / Web security gateway - URL filter / Content inspection
- Malware inspection
- Spam filter
- CSU/DSU
- Router, Switch
- Firewall
- IDS/IPS
- Bandwidth shaper
- VPN endpoint
what is Load balancers
- Distribute the load
– Multiple servers
– Invisible to the end-user - Large-scale implementations
– Web server farms, database farms - Fault tolerance
– Server outages have no effect - Very fast convergence
what is Load balancers features
- Configurable load - Manage across servers
- TCP offload - Protocol overhead
- SSL offload - Encryption/Decryption
- Caching - Fast response
- Prioritization - QoS
- Content switching - Application-centric balancing
what is Proxy server
- An intermediate server
– Client makes the request to the proxy
– The proxy performs the actual request
– The proxy provides results back to the client - Useful features
– Access control, caching, URL filtering, content scanning
what is SCADA / ICS
- Supervisory Control and Data Acquisition System
– Large-scale, multi-site Industrial Control Systems (ICS) - PC manages equipment
– Power generation, refining,
manufacturing equipment
– Facilities, industrial, energy, logistics - Distributed control systems
– Real-time information
– System control
– Requires extensive segmentation
– No access from the outside
what is Legacy and embedded systems
- Legacy systems
– Another expression for “really old”
– May also be “really important”
– Learning old things can be just as important as
learning the new things - Embedded systems
– Purpose-built device
– Not usual to have direct access to
the operating system
– Alarm system, door security, time card syste
what is IoT (Internet of Things) devices
- Appliances
– Refrigerators - Smart devices
– Smart speakers respond to voice commands - Air control
– Thermostats, temperature control - Access
– Smart doorbells - May require a segmented network
– Limit any security breaches
what is IPv4 addresses
IPv4 is the primary protocol for everything we do
– You probably won’t configure anything else
* IPv6 is now part of all major operating systems
– And the backbone of our Internet infrastructure
* Internet Protocol version 4
– OSI Layer 3 address
what is IPv6 addresses
IPv6 addresses
* Internet Protocol v6 - 128-bit address
– 340,282,366,920,938,463,463,374,607,431,768,211,456
addresses (340 undecillion)
– 6.8 billion people could each have
5,000,000,000,000,000,000,000,000,000 addresses
how to Networking with IPv6 addresses
IP Address, e.g., 192.168.1.165
– Every device needs a unique IP address
* Subnet mask, e.g., 255.255.255.0
– Used by the local device to determine its subnet
– The subnet mask isn’t (usually) transmitted
across the network
* Default gateway, e.g., 192.168.1.1
– The router that allows you to communicate
outside of your local subnet
– The default gateway must be an IP address
on the local subnet
DNS servers w/ IP
- We remember names
– professormesser.com, google.com, youtube.com - Internet routers don’t know names
– Routers only know IP addresses - Something has to translate between
names and IP addresses
– Domain Name Services - You configure two DNS servers in
your IP configuration
– That’s how important it is
Assigning IP Addresses DHCP
- IPv4 address configuration used to be manual
– IP address, subnet mask, gateway,
DNS servers, NTP servers, etc. - October 1993 - The bootstrap protocol (BOOTP)
- BOOTP didn’t automatically define everything
– Some manual configurations were still required
– BOOTP also didn’t know when an
IP address might be available again - Dynamic Host Configuration Protocol (DHCP)
– Initially released in 1997,
updated through the years
– Provides automatic address / IP configuration
for almost all devices
The DHCP Process (DORA)
- Step 1: Discover - Client to DHCP Server
– Find all of the available DHCP Servers - Step 2: Offer - DHCP Server to client
– Send some IP address options to the client - Step 3: Request - Client to DHCP Server
– Client chooses an offer and makes a formal request - Step 4: Acknowledgment - DHCP Server to client
– DHCP server sends an acknowledgment to the client
Assigning IP Addresses Turning dynamic into static
- DHCP assigns an IP address from the first available from a
large pool of addresses
– Your IP address will occasionally change - You may not want your IP address to change
– Server, printer, or personal preference - Disable DHCP on the device
– Configure the IP address information manually
– Requires additional administration - Better: Configure an IP reservation on the DHCP server
– Associate a specific MAC address with an IP address
Assigning IP Addresses Avoid manual configurations
- No DHCP server reservation
– You configure the IP address manually - Difficult to change later - You must visit the device again
- A DHCP reservation is preferable
– Change the IP address from the DHCP server
Automatic Private IP Addressing (APIPA)
A link-local address - No forwarding by routers
* IETF has reserved 169.254.0.0 through 169.254.255.255
– First and last 256 addresses are reserved
– Functional block of169.254.1.0 through 169.254.254.255
* Automatically assigned
– Uses ARP Address Resolution Protocol to confirm the address isn’t currently in use
DNS Configuration
- Translates human-readable names
into computer-readable IP addresses
– You only need to remember
www.ProfessorMesser.com - Hierarchical
– Follow the path - Distributed database
– Many DNS servers
– 13 root server clusters (over 1,000 actual servers)
– Hundreds of generic top-level domains (gTLDs) -
.com, .org, .net, etc.
– Over 275 country code top-level domains (ccTLDs) -
.us, .ca, .uk, etc.
what are DNS records
- Resource Records (RR)
– The database records of domain name services - Over 30 record types
– IP addresses, certificates, host alias names, etc. - These are important and critical configurations
– Make sure to check your settings, backup, and test!
what are Address records (A) (AAAA)
- Defines the IP address of a host
– This is the most popular query - A records are for IPv4 addresses
– Modify the A record to change the
host name to IP address resolution - AAAA records are for IPv6 addresses
– The same DNS server, different records
-DNS Configuration Mail exchanger record (MX)
Determines the host name for the mail server - this isn’t an IP address; it’s a name
what are Text records (TXT
- Human-readable text information
– Useful public information
– Was originally designed for
informal information - Can be used for verification purposes
– If you have access to the DNS,
then you must be the administrator
of the domain name - Commonly used for email security
– External email servers validate
information from your DNS
what is Sender Policy Framework (SPF)
- SPF protocol
– A list of all servers authorized to send emails
for this domain
– Prevent mail spoofing
– Mail servers perform a check to see if incoming mail
really did come from an authorized host
what is Domain Keys Identified Mail (DKIM)
- Digitally sign a domain’s outgoing mail
– Validated by mail servers, not usually
seen by the end user
– The public key is in the DKIM TXT record
what is DMARC
- Domain-based Message Authentication, Reporting,
and Conformance (DMARC)
– Prevent unauthorized email use (spoofing)
– An extension of SPF and DKIM - You decide what external email servers should do with
emails that don’t validate through SPF or DKIM
– That policy is written into a DMARC TXT record
– Accept all, send to spam, or reject the email
– Compliance reports can be sent to the email administrator
DHCP Configuration –Scope properties
- IP address range
– And excluded addresses - Subnet mask
- Lease durations
- Other scope options
– DNS server
– Default gateway
– VOIP servers
DHCP Configuration –DHCP pools
- Grouping of IP addresses
– Each subnet has its own scope
– 192.168.1.0/24
– 192.168.2.0/24
– 192.168.3.0/24
– … - A scope is generally a single contiguous
pool of IP addresses
– DHCP exceptions can be made inside of the scope
DHCP Configuration –DHCP address assignment
- Dynamic assignment
– DHCP server has a big pool of addresses to give out
– Addresses are reclaimed after a lease period - Automatic assignment
– Similar to dynamic allocation
– DHCP server keeps a list of past assignments
– You’ll always get the same IP address
DHCP Configuration –DHCP address allocation
- Address reservation
– Administratively configured - Table of MAC addresses
– Each MAC address has a matching IP address - Other names
– Static DHCP Assignment, Static DHCP,
Static Assignment, IP Reservation
DHCP Configuration –DHCP leases
- Leasing your address
– It’s only temporary
– But it can seem permanent - Allocation
– Assigned a lease time by the DHCP server
– Administratively configured - Reallocation
– Reboot your computer
– Confirms the lease - Workstation can also manually release the IP address
– Moving to another subnet
DHCP Configuration –DHCP renewal
- T1 timer
– Check in with the lending DHCP server to renew
the IP address
– 50% of the lease time (by default) - T2 timer
– If the original DHCP server is down, try rebinding
with any DHCP server
– 87.5% of the lease time (7/8ths)
LANs
Local Area Networks
* A group of devices in the same broadcast domain
Virtual LANs
Virtual Local Area Networks
* A group of devices in the same broadcast domain
* Separated logically instead of physically
Configuring VLANs
- Virtual Local Area Networks
– A group of devices in
the same broadcast domain
VPNs
- Virtual Private Networks
– Encrypted (private) data traversing a public network - Concentrator
– Encryption/decryption access device
– Often integrated into a firewall - Many deployment options
– Specialized cryptographic hardware
– Software-based options available - Used with client software
– Sometimes built into the OS
Client-to-Site VPNs
- On-demand access from a remote device
– Software connects to a VPN concentrator - Some software can be configured as always-on
Internet Connection Types – Satellite networking
- Communication to a satellite
– Non-terrestrial communication - High cost relative to terrestrial networking
– 50 Mbit/s down, 3 Mbit/s up are common
– Remote sites, difficult-to-network sites - High latency
– 250 ms up, 250 ms down
– Starlink advertises 40 ms and is working on 20 ms - High frequencies - 2 GHz
– Line of sight, rain fade
Internet Connection Types – Fiber
- High speed data communication
– Frequencies of light - Higher installation cost than copper
– Equipment is more costly
– More difficult to repair
– Communicate over long distances - Large installation in the WAN core
– Supports very high data rates
– SONET, wavelength division multiplexing - Fiber is slowly approaching the premises
– Business and home use
Internet Connection Types – Cable broadband
- Broadband
– Transmission across multiple frequencies
– Different traffic types - Data on the “cable” network
– DOCSIS (Data Over Cable Service Interface
Specification) - High-speed networking
– 50 Mbits/s through 1,000+ Mbit/s are common - Multiple services
– Data, voice, video
Internet Connection Types – DSL
DSL
* ADSL (Asymmetric Digital Subscriber Line)
– Uses telephone lines
* Download speed is faster than the upload speed
(asymmetric)
– 200 Mbit/s downstream / 20 Mbit/s upstream
are common
– ~10,000 foot limitation from the central office (CO)
– Faster speeds may be possible if closer to the CO
Internet Connection Types – Cellular networks
- Mobile devices
– “Cell” phones - Separate land into “cells”
– Antenna covers a cell with certain frequencies - Tethering
– Turn your phone into a wireless router - Mobile hotspot
– Standalone devices
– Use your phone for other things
Internet Connection Types – WISP
- Wireless Internet Service Provider
– Terrestrial internet access using wireless - Connect rural or remote locations
– Internet access for everyone - Many different deployment technologies
– Meshed 802.11
– 5G home internet
– Proprietary wireless - Need an outdoor antenna
– Speeds can range from ~ 10 to 1,000 megabits per second
Network Types – LAN
- Local Area Network
– Local is relative - A building or group of buildings
– High-speed connectivity - Ethernet and 802.11 wireless
– Any slower and it isn’t “local”
Network Types – WAN
- Wide Area Network
– Spanning the globe - Generally connects LANs across a distance
– And generally much slower than the LAN - Many different WAN technologies
– Point-to-point serial, MPLS, etc.
– Terrestrial and non-terrestrial
Network Types – PAN
- Personal Area Network
– Your own private network
– Bluetooth, IR, NFC - Automobile
– Audio output
– Integrate with phone - Mobile phone - Wireless headset
- Health
– Workout telemetry, daily reports
Network Types – MAN
- Metropolitan Area Network
– A network in your city
– Larger than a LAN, often smaller than a WAN - Historically MAN-specific topologies
– Metro Ethernet - Common to see government ownership
– They “own” the right-of-way
Network Types – SAN
SAN
* Storage Area Network (SAN)
– Looks and feels like a local storage device
– Block-level access
– Very efficient reading and writing
* Requires a lot of bandwidth
– May use an isolated network and high-speed
network technologies
Network Types – WLAN
Wireless LAN
– 802.11 technologies
* Mobility
– Within a building
– In a limited geographical area
* Expand coverage with additional access points
– Downtown area
– Large campus
Network Tools – Cable crimper
- “Pinch” the connector onto a wire
– Coaxial, twisted pair, fiber - Connect the modular connector to
the Ethernet cable
– The final step of the process - Metal prongs are pushed through the insulation
– The plug is also permanently pressed
onto the cable sheath
Network Tools – Cable crimper best practices
- Get a good crimper
– And a good pair of electrician’s scissors / cable snips
– And a good wire stripper - Make sure you use the correct modular connectors
– Differences between wire types - Practice, practice, practice
– It won’t take long to become proficient
Network Tools –WiFi analyzer
- Wireless networks are
incredibly easy to monitor
– Everyone “hears” everything - Purpose-built hardware or
mobile device add-on
– Specializes in 802.11 analysis - Identify errors and interference
– Validate antenna location and installation
Network Tools –Tone generator
- Where does that wire go?
– Follow the tone - Tone generator
– Puts an analog sound on the wire - Inductive probe
– Doesn’t need to touch the copper
– Hear through a small speaker
Network Tools –Using the tone generator and probe
- Easy wire tracing
– Even in complex environments - Connect the tone generator to the wire
– Modular jack, coax, punch down connectors - Use the probe to locate the sound
– The two-tone sound is easy to find
Network Tools –Punch-down tools
- “Punch” a wire into a wiring block
– 66 block, 110 block, and others - Can be tedious
– Every wire must be
individually punched - Trims the wires during the punch
– Very efficient process
Network Tools –Punch-down best-practices
- Organization is key
– Lots of wires,
– Cable management - Maintain your twists
– Your Category 6A cable will thank you later - Document everything
– Written documentation, tags, graffiti
Network Tools –Cable testers
- Relatively simple
– Continuity test - Can identify missing pins
– Or crossed wires - Not usually used for frequency testing
– Crosstalk, signal loss, etc.
Network Tools –Loopback plugs
- Useful for testing physical ports
– Or fooling your applications - Serial / RS-232 (9 pin or 25 pin)
- Network connections
– Ethernet, T1, Fiber - These are not cross-over cables
Network Tools –Taps and Port Mirrors
- Intercept network traffic
– Send a copy to a packet capture device - Physical taps
– Disconnect the link, put a tap in the middle
– Can be an active or passive tap - Port mirror
– Port redirection, SPAN (Switched Port ANalyzer)
– Software-based tap
– Limited functionality, but can work well in a pinch
