Domain 2: Networking Flashcards
IP
Internet Protocol
IP Payloads
TCP (Transmission Control Protocol)
UDP (User Datagram Protocol)
“In the clear”
Not encrypted
How does TCP work?
Requires formal setup/teardown process to establish protocol. Flow control so one side doesn’t get data too fast.
-called reliable system because data is confirmed to reach destination.
Examples of TCP
HTTPS and SSH
How does UDP work?
No formal setup process, for real time communication.
-called unreliable system as there’s no conformation that data was sent/received.
Examples of UDP
DHCP and TFTP
Multiplexing
Multiple applications at the same time; data signals use the same channel without interference.
IPv4 Sockets
~Server IP address, protocol, Server application port number,.
~Client IP address, protocol, client port number.
Non-Ephemeral Ports
Permanent; ports 0-1023. Usually on a server or service.
Ephemeral Port
Temporary port numbers; ports 1024-65,535. Determined in real time by client.
Most servers use…
Non-Ephemeral ports.
Key fact about ports
Ports are for communication, not security.
Key fact about TCP/UDP using ports
TCP and UDP can use the same port numbers at the same time.
FTP (File Transfer Protocol)
TCP 20/21. File transfer between systems
Telnet
TCP 23; in the clear remote command console access
SSH (Secure Shell)
TCP 22; Encrypted communication for command console
SMTP (Simple Mail Transfer Protocol)
TCP 25; only sending mail, not receiving
DNS (Domain Name System)
UDP 53; converts names to IP addresses. Critical resources
-www.professermesser.com =162.159.246.164
HTTP/HTTPS (Hypertext Transfer Protocol/Secure)
TCP 80: http; web server communication
TCP 443: HTTPS; web server communication + encryption
POP3/IMAP4
both receive emails from email server.
~Post Office Protocol v3 (TCP 110). Basic mail transfer functionality.
~Internet Message Access Protocol v4 (TCP 143). includes management of email inboxes from multiple clients
RDP (Remote Desktop Protocol)
TCP 3389; share desktop control from remote location.
~can connect to entire desktop or application.
~clients for Windows, macOS, Linux, Unix, iPhone, Android, and others
SMB (Server Message Block)
Windows file/printer sharing protocol.
~uses NetBIOS.
NetBIOS name services (nbname)
UDP 137
NetBIOS Datagram service (nbdatagram)
UDP 138
NetBIOS session service (nbsession)
TCP 139
NetBIOS-less
TCP 445; direct SMB communication over TCP without NetBIOS transport.
SMB is also referred to as
CIFS (Common Internet File System)
AFP (Apple Filing Protocol)
TCP 548; file services in macOS. Copy, move, delete files.
AFP works with…
SLP (Service Location Protocol). TCP/UDP 427.
DHCP (Dynamic Host Configuration Protocol)
UDP 67/68; automated configuration of IP addresses, subnet mask and other options.
~requires DHCP server.
Dynamic/pooled (DHCP)
IP addresses are assigned in real-time from a pool of addresses.
DHCP Reservation
Addresses are assigned by MAC address in the DHCP server.
LDAP (Lightweight Directory Access Protocol)
TCP 389; store and retrieve information in a network directory
SNMP (Simple Network Management Protocol)
Gather statistics from network devices.
~Traps: UDP 162
~Queries: UDP 161
SNMP v1
Original.
~structured tables, not encrypted.
SNMP v2
A good step ahead.
~data type enhancements. Bulk transfers. Non encrypted.
SNMP v3
Secure standard.
~message integrity. Authentication. Encrypted.
Router
Routes traffic between IP subnets. Often connects diverse network types (LAN, WAN, copper, fiber)
Switch
Briding done in hardware. ASIC (Application-specific integrated circuit). Forwards traffic based on data link address.
~core of an enterprise network.
PoE
Power over Ethernet.
Unmanaged Switch
Very few configuration options. Fixed configuration (No VLANs). Very little integration with other devices (no management protocols). Low price point.
Managed Switch
VLAN support. Traffic priority (voice traffic priority higher). Redundancy support (STP). Port mirroring. External management (SNMP)
STP
Spanning Tree Protocol
Access Point
Wireless connectivity for local network (Not a wireless router). Also called a bridge.
~makes forwarding decisions based on MAC address.
Patch Panel
Combination of punch-down blocks and RJ-45 connectors. Can easily be changed.
Firewall
Filters traffic by port number.
~OSI Layer 4 (TCP/UDP)
Can encrypt traffic in/out of network.
Most firewalls can be…
Layer 3 devices (routers)
How does PoE work?
Power is provided on an Ethernet cable. Power provided at the switch
PoE standard
PoE: IEEE 802.3af-2003
~15.4 watts DC, 350 mA max current.
~802.3 standard
PoE+
IEEE 802.3at-2009
~25.5 watts DC, 600mA max current.
~802.3 standard
PoE++
IEEE 802.3bt-2018
~51W (Type 3), 600mA max
~71.3W (Type 4), 960mA max.
~PoE with 10GBASE-T
Hub
“Multi-port repeater” (traffic going in one port is repeated to all others). Half-duplex. Less efficient as traffic increases.
~found in 10Mb and 100Mb, not common.
Broadband
Transmission across multiple frequencies. Data on “cable” network. Speeds up to 1Gbps (depends on provider)
DOCSIS
Data Over Cable Service Interface Specification.
DSL Modem
ADSL (Asymmetric Digital Subscriber Line)
~uses telephone lines.
Download speed faster than upload speed (Asymmetric).
ONT (Optical Network Terminal)
Commedt the ISP fiber network to copper network.
~terminal box on side of building.
NIC (Network Interface Card)
The fundamental network device.
~every device on the network has a NIC.
Specific to the network type (WAN, Wireless, Ethernet). Often built-in motherboard (or added as expansion card).
SDN (Software Defined Networking)
Networking devices have different functional planes of operation. Splits functions into separate logical units.
Infrastructure Layer/Data Plane
Process the network frames and packets (forwarding, trunking, encrypting, NAT).
Application layer/management plane and Control layer/plane
Control Layer/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
