Networks, TCP/IP, and
Network-Based attacks
Networks, TCP/IP, and
Network-Based attacks
Lesson 2
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Understanding Network Fundamentals & Security Threats: Networks, TCP/IP & Attacks - Prof. , Study notes of Information Technology
An overview of computer networks, tcp/ip protocols, network topologies, and common network-based attacks. It covers the concept of networks, different types of network topologies, the osi and tcp/ip reference models, and various network-based attacks such as sniffing, spoofing, hijacking, and denial of service. Students will gain a solid understanding of the importance of network security and the methods used to exploit vulnerabilities.
Typology: Study notes
Pre 2010
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Networks, TCP/IP, and
Network-Based attacks
Networks, TCP/IP, and
Network-Based attacks
Lesson 2
Review
Is an ROI from Security
Possible?
Review
Is an ROI from Security
Possible?
Security as an ROI
Improved Security ROI
Security that provides savings in the budget
Security that provides additional revenue
NetworksNetworks
What is a network?
Two or more systems connected together LAN (local area network) WAN (Wide area network) MAN (metropolitan area network)
Network TopologiesNetwork Topologies
Topology – the physical arrangement of the network. Completely Connected Star Ring Bus Characteristics
of connections
of “hops”
Addition of new nodes Fairness Collisions and points of failure
Network Topologies -- StarNetwork Topologies -- Star
Adv: distance = 2 hops connections = n- DisAdv: 1 point of failure Fairness? Addition of new nodes? Congestion(collisions)?
Network Topologies -- RingNetwork Topologies -- Ring
Adv: avg dist = (n-1)/2 hops connections = n DisAdv: many points of failure Fairness (token)? Addition of new nodes? Congestion(collisions)?
ProtocolsProtocols
A protocol is an agreed upon format for exchanging
information.
A protocol will define a number of parameters:
Type of error checking Data compression method Mechanisms to signal reception of a transmission
There are a number of protocols that have been
established in the networking world.
OSI Reference ModelOSI Reference Model
(^) ISO standard describing 7 layers of protocols Application: Program-level communication Presentation: Data conversion functions, data format, data encryption Session: Coordinates communication between endpoints. Session state maintained for security. Transport: end-to-end transmission, controls flow of data Network: routes data from one system to the next Data Link: Handles physical passing of data between nodes Physical: Manages the transmission media/HW connections (^) Abstraction is the principle, you only have to communicate with the layer directly above and below
OSI and TCP/IP comparisonOSI and TCP/IP comparison
OSI Model Application Presentation Session Transport Network Data-link Physical TCP/IP Protocol Suite NFS FTP, Telnet, SSH, SMTP SMB HTTP, NNTP RPC TCP,UDP IP ICMP ARP Physical Application-level protocols Network-level protocols
TCP/IP Protocol SuiteTCP/IP Protocol Suite
User Process User Process User Process User Process TCP UDP IP HW Interface ARP RARP ICMP IGMP Media
Demultiplexing of a
received Ethernet Frame
Demultiplexing of a
received Ethernet Frame
application application application application TCP UDP ICMP IGMP IP ARP RARP Ethernet driver Incoming Frame
IP DatagramIP Datagram
32 Bits Source Address Destination Address Time-to-live Protocol Header Checksum Version head lngth Type of Service Total Length Identification Flags Frag Offset Options (if any) Data
Establishment of a TCP
connection
(“3-way Handshake”)
Establishment of a TCP
connection
(“3-way Handshake”) client Server
SYN
Client sends connection request, Specifying a port to connect to On the server. client Server
SYN/ACK
Server responds with both an acknowledgement and a queue for the connection. client Server
ACK
Client returns an acknowledgement and the circuit is opened.
User Datagram Protocol
(UDP)
User Datagram Protocol
(UDP)
UDP is a connectionless transport layer protocol that provides no reliability and has no mechanism for connection establishment or termination. UDP makes no guarantee about packet delivery. This “fire and forget” nature means a packet is placed on the network and you just hope it gets to where it was supposed to go to. UDP is commonly used for network services that are not sensitive to an occasional lost (dropped) packet. Because of the relative overall reliability of the network, it has become less important to have a guaranteed service and thus UDP is a good choice for many streaming services.