Network Design Flashcards
OSI Model
Application Presentation Session Transport Network Data Link Physical
Physical Layer
§ Represents the actual network cables and radio waves used to carry data over a network
§ Bits
Data Link Layer
§ Describes how a connection is established, maintained, and transferred over the physical layer and uses physical addressing (MAC addresses)
§ Frames
Network Layer
§ Uses logical address to route or switch information between hosts, the network, and the internetworks
§ Packets
Transport Layer
§ Manages and ensures transmission of the packets occurs from a host to a destination using either TCP or UDP
§ Segments (TCP) or Datagrams (UDP)
Session Layer
Manages the establishment, termination, and synchronization of a session over the network
Presentation Layer
Translates the information into a format that the sender and receiver both understand
Application Layer
§ Layer from which the message is created, formed, and originated
§ Consists of high-level protocols like HTTP, SMTP, and FTP
MAC Flooding
§ Attempt to overwhelm the limited switch memory set aside to store the MAC addresses for each port
§ Switches can fail-open when flooded and begin to act like a hub
MAC Flooding
§ Attempt to overwhelm the limited switch memory set aside to store the MAC addresses for each port
§ Switches can fail-open when flooded and begin to act like a hub
MAC Spoofing
Occurs when an attacker masks their own MAC address to pretend they have the MAC address of another device
MAC Spoofing is often combined with an ARP spoofing attack
MAC Spoofing - Protection
§ Limit static MAC addresses accepted
§ Limit duration of time for ARP entry on hosts
§ Conduct ARP inspection
Routers operate at OSI Layer
Routers operate at OSI Layer 3 (Network)
Routers rely on a _______ to determine the proper
destination
Routers rely on a packet’s IP Addresses to determine the proper
destination
De-Militarized Zone
A segment isolated from the rest of a private network by one or more firewalls that accepts connections from the Internet over designated ports
Focused on providing controlled access to publicly available servers that are hosted within your organizational network
Extranet
Specialized type of DMZ that is created for your partner organizations to access over a wide area network
Bastion Hosts
§ Hosts or servers in the DMZ which are not configured with any services that run on the local network
§ To configure devices in the DMZ, a jumpbox is utilized
Jumpbox
§ A hardened server that provides access to other hosts within the DMZ § An administrator connects to the jumpbox and the jumpbox
connects to hosts in the DMZ
Network Access Control
§ Security technique in which devices are scanned to determine its current state prior to being allowed access onto a given network
§ If a device fails the inspection, it is placed into digital quarantine
Persistent Agents
Network Access Control
A piece of software that is installed on the device requesting access to the network
Non-Persistent Agents
Network Access Control
Uses a piece of software that scans the device remotely or is installed and subsequently removed after the scan
_________ standard is used in port-based NAC
IEEE 802.1x standard is used in port-based NAC
Switch Spoofing
Attacker configures their device to pretend it is a switch and uses it to negotiate a trunk link to break out of a VLAN
Double Tagging
§ Attacker adds an additional VLAN tag to create an outer and inner tag
§ Prevent double tagging by moving all ports out of the default VLAN group
Subnetting
§ Act of creating subnetworks logically through the manipulation of IP addresses § Efficient use of IP addresses § Reduced broadcast traffic § Reduced collisions § Compartmentalized
VLANs Benefits
o Segment the network o Reduce collisions o Organize the network o Boost performance o Increase security
Network Address Translation
§ Process of changing an IP address while it transits across a router
§ Using NAT can help us hide our network IPs
Port Address Translation
Router keeps track of requests from internal hosts by assigning them random high number ports for each request
Class A IP Range
10.0.0.0 to 10.255.255.255
Class B IP Range
172.16.0.0 to 172.31.255.255
Class C IP Range
192.168.0.0 to 192.168.255.255
