Day_1 Network Device

• Network


  A digital communications network which allows nodes to share resources
• Types of network nodes

  • Router
  • Switch
  • Firewall
  • Server
  • Client
• Client


  A device that accesses a service made available by a server
• Server


  A device that provides functions or services for clients
• The same device can be a client in some situations and a server in other situations
• Switch


  A device used to forward traffic within a LAN (local area network)
• Switches cannot connect directly to the Internet
• Router


  A device used to provide connectivity between LANs and over the Internet
• Routers have fewer network interfaces than switches
• Switches are used to forward data within a LAN, while routers are used to send data between LANs and over the Internet
• Routers


  • Have network interfaces on the back
  • Have relatively few network interfaces compared to switches
• Switches vs Routers


  Switches are used to forward data within a LAN, routers are used to provide connectivity BETWEEN LANs
• Routers


  Are used to send data over the Internet
• Firewalls


  • Specialty network security devices that control network traffic entering and exiting your network
  • Can be placed 'outside' or 'inside' the network
  • Must be configured with security rules to determine which network traffic should be allowed and which should be denied
• Cisco firewalls


  • ASA5500-X series
  • Firepower 2100 series
• Next-generation firewalls


  Include more modern and advanced filtering capabilities
• Host-based firewalls


  Software applications that filter traffic entering and exiting a host machine, like a PC
• Even in a network with a hardware firewall, each PC should include a software firewall as an extra line of defense
• Cisco network devices


  • ISR 1000
  • ISR 4000
  • ISR 900
  • Catalyst 9200 series switch
• An attacker in the Internet could attack the enterprise network
• Firewalls should block the attacker from accessing anything inside the network
• If PC1 in New York tries to access SRV1 in Tokyo, the firewalls should permit the traffic through
• The return traffic from SRV1 to PC1 should be allowed as well