Switches
Forward frames between nodes in a cabled network
WAP
Wireless Access Point
Routers
Forward packets around an internet based on IP addresses
Firewalls
Apply Access Control List (ACL) to filter traffic passing in or out of a network segment
- works a the OSI Model Network layer (3)
Load Balancers
Network appliance which distributes traffic btwn network segments or servers to optimize performance
- works at the OSI Model Transport layer (4) or higher
DNS
Domain Name System
OSI Model - Layer 1
Layer 1: Physical PDU: bits HW: Hubs, net tap, repeaters Addressing: none Protocols: UTP, STP, COAX, Fiber, TDM, FDM Control: node
OSI Model Layer 2
Layer: Datalink - Connects nodes inside a LAN together - Nodes to Nodes
PDU: Frame
HW: Switch, Bridge, WAP
Addressing: MAC address (Physical Address), VLAN id
Protocols: Ethernet, PPP, LLC
Control: MAC Filtering
Address Resolution Protocol (ARP) between Physical and Datalink layers
OSI Model Layer 3
Layer: Network - Connects LANs together - LAN to LAN
PDU: Packet
HW: Router, Layer 3 Switches
Addressing: IP Addresses (Logical Addresses)
Protocols: IP, ICMP, IPSec, IGMP
Control: Packet Filtering Firewall
OSI Model Layer 4
Layer: Transport - End to end connections PDU: Segment HW: Load Balancer, Firewall Addressing: Logical Port Numbers Protocols: TCP, UDP, optionally SSL/TLS Control: Packet Filtering Firewall
OSI Model Layer 5
Layer: Session - Interhost Communication
- Synchronize upper layers with lower layers
- allows session establishment btwn processes
PDU:
HW:
Addressing:
Protocols:
OSI Model Layer 6
Layer: Presentation - Syntax layer
- Formats the data as needed
PDU: Data HW: Addressing: Protocols: Control: NGFW or App layer Firewall
OSI Model Layer 7
Layer: Application - End Used Layer PDU: Data HW: Addressing: Protocols: HTTP(TCP 80), HTTPS(TCP 443), SMTP(TCP 25), FTP (20, 21) Control: NGFW or App Layer Firewall
ARP
Address Resolution Protocol
Firewall
DNS
Domain Name System
- Sits btwn Transport Layer (4) and the upper layers (5-7)
IP Addresses come from ?
Locally:
DHCP - Dynamic Host Configuration Protocol
- Service to assign network IP addresses to client upon connection
Public:
- Internet Service Provider (ISP), assigned when get the service
Private IP ranges
IPv4 vs IPv6
IPv4
IPv6
Network Segmentation
Network Segment
Segregation
VLAN
Virtual Local Area Network
DMZ
Demilitarized Zones
Screened Subnet
PNAC
Port-based Network Access Control
Network Access Control