Networking Flashcards
(50 cards)
1
Q
UDP Name
A
User Datagram Protocol
2
Q
UDP Protocol
A
- Connectionless
- No formal open or 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
3
Q
TCP & UDP
A
- Transported inside of IP
- Encapsulated by the IP protocol
- Two ways to move data from place to place
- Different features for different applications
- OSI Layer 4
- The transport layer
- Multiplexing
- Use many different applications at the same time
4
Q
TCP Name
A
Transmission Control Protocol
5
Q
TCP Protocol
A
- 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
6
Q
IPv4 sockets
A
Server IP address, protocol,
server application port number
• Client IP address, protocol, client port number
7
Q
Non-ephemeral ports
A
permanent port numbers
• Ports 0 through 1,023
8
Q
Ephemeral ports
A
– temporary port numbers
• Ports 1,024 through 65,535
• Determined in real-time by the client
9
Q
FTP Name
A
File Transfer Protocol
10
Q
FTP Protocol
A
- tcp/20 (active mode data), tcp/21 (control)
- Transfers files between systems
- Authenticates with a username and password
- Some systems use a generic/anonymous login
- Full-featured functionality
- List, add, delete, etc.
11
Q
SSH Name
A
Secure Shell
12
Q
SSH Protocol
A
- Encrypted communication link - tcp/22
* Looks and acts the same as Telnet
13
Q
Telnet
A
- Telnet – Telecommunication Network - tcp/23
- Login to devices remotely
- Console access
- In-the-clear communication
- Not the best choice for production systems
14
Q
SMTP Name
A
Simple Mail Transfer Protocol
15
Q
SMTP Protocol
A
• Server to server email transfer - tcp/25
• Also used to send mail from a device to a mail server
• Commonly configured on mobile devices
and email clients
16
Q
DNS Name
A
Domain Name System
17
Q
DNS Protocol
A
- Converts names to IP addresses - udp/53
- www.professormesser.com = 162.159.246.164
- These are very critical resources
- Usually multiple DNS servers are in production
18
Q
HTTP & HTTPS
A
- Hypertext Transfer Protocol - tcp/80
- Communication in the browser
- And by other applications
- In the clear or encrypted - HTTPS - tcp/443
- Supported by nearly all web servers and clients
19
Q
RDP Name
A
Remote Desktop Protocol
20
Q
RDP Name
A
Remote Desktop Protocol
21
Q
RDP Protocol
A
• Share a desktop from a remote location over tcp/3389
• Remote Desktop Services on many Windows versions
• Can connect to an entire desktop
or just an application
• Clients for Windows, macOS, Linux, Unix,
iPhone, Android, and others
22
Q
SMB Name
A
Server Message Block
23
Q
SMB Protocol
A
• Direct over tcp/445 (NetBIOS-less)
• Direct SMB communication over TCP
without the NetBIOS transport.
- Protocol used by Microsoft Windows
- File sharing, printer sharing
- Also called CIFS (Common Internet File System)
24
Q
NetBIOS name services
A
udp/137 Register, remove, and find windows services by name.
25
NetBIOS Datagram service
udp/138 Windows connection-less data transfer
26
NetBIOS Session Service
tcp/139 Windows connection oriented data transfer.
27
AFP Name
Apple Filing Protocol
28
AFP Protocol
* File services in macOS
* tcp/548
* Works with SLP (Service Location Protocol)
* tcp/427 and udp/427
* Populates the list of available devices
* File management
* Copy, move, delete files
29
DHCP Name
- Dynamic Host Configuration Protocol
30
DHCP Protocol
• Automated configuration of IP address, subnet mask
and other options
• udp/67, udp/68
• Requires a DHCP server
• Server, appliance, integrated into a SOHO router, etc.
• Dynamic / pooled
• IP addresses are assigned in real-time from a pool
• Each system is given a lease and must renew
at set intervals
• DHCP reservation
• Addresses are assigned by MAC address
in the DHCP server
• Quickly manage addresses from one location
31
LDAP Name
(Lightweight Directory Access Protocol)
32
LDAP Protocol
tcp/389
• Store and retrieve information in a network directory
• Commonly used in Microsoft Active Directory
33
SNMP Name
Simple Network Management Protocol
34
SNMP Protocol
* Gather statistics/ metrics from network devices to manage devices.
* Queries: udp/161
* Traps: udp/162
* v1 – The original
* Structured tables, in-the-clear
* v2 – A good step ahead
* Data type enhancements
* Bulk transfers, still in-the-clear
* v3 – A secure standard
* Message integrity
* Authentication, encryption
35
ASIC
Application-specific integrated circuit
36
802.11a
5 Ghz 54megabits per second (Mbit/s) 1/3 range of 2.4 Ghz
37
802.11b
2.4 Ghz 11 megabits (Mbits/s)
| Frequency conflict. 22 Mhz channel
38
802.11g
2.Ghz 54 megabits (Mbits/s)
| Frequency conflict. 20 Mhz channel
39
802.11n
```
• 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 4 MIMO
• Multiple-input multiple-output
• Multiple transmit and receive antennas
4MIMO 150Mbit/s 600 Mbit/s
20 or 40 Mhz (bonded)
```
40
802.11ac
• 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
• 8 MU-MIMO streams
• Twice as many streams as 802.11n
8MU-MIMO 866.7Mbit/s ~6.8 Gbit/s
40Mhz for 802.11n stations
80 Mhz for 802.11ac stations
160 Mhz optional.
41
Zigbee
* Internet of Things networking
* Open standard - IEEE 802.15.4 PAN
* Alternative to WiFi and Bluetooth
* Longer distances than Bluetooth
* Less power consumption than WiFi
* Mesh network of all Zigbee devices in your home
* Light switch communicates to light bulbs
* Tell Amazon Echo to lock the door
* Uses the ISM band
* Industrial, Scientific, and Medical
* 900 MHz and 2.4 GHz frequencies in the US
42
Z-Wave
```
• Proprietary home automation networking
• Internet of Things (IoT)
• Control lights, locks, garage doors, etc.
• Wireless mesh networking
• Nodes can hop through
other nodes on
the way to the destination
• Uses the ISM band
• Industrial, Scientific,
and Medical
• 900 MHz frequencies in the US
• No conflicts with 802.11
```
43
```
• 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
```
Network Interface Card (NIC)
44
```
Receive signal, regenerate, resend
• No forwarding decisions to make
• Common use
• Boost copper or fiber connections
• Convert one network media to another
• Extend wireless network reach
```
Repeater
45
* “Multi-port repeater”
* Traffic going in one port is repeated to every other port
* Everything is half-duplex
* Becomes less efficient as network speeds increase
* 10 megabit / 100 megabit
* Difficult to find today
Hub
46
• Imagine a switch with two to four ports
• Makes forwarding decisions in software
• Connects different physical networks
• Can connect different topologies
• Gets around physical network size limitations /
collisions
• Distributes traffic based on MAC address
• A modern bridge is a wireless access point
• Bridges wired Ethernet to wireless
Bridge
47
* 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
Switches
48
* 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
Unmanaged switches
49
* VLAN support
* Interconnect with other switches via 802.1Q
* Traffic prioritization
* Voice traffic gets a higher priority
* Redundancy support
* Spanning Tree Protocol (STP)
* External management
* Simple Network Management Protocol (SNMP)
* Port mirroring
* Capture packets
Managed Switches
50
• 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
Routers
