Networks And Protocols

Front 1

Well Known Ports

Back 1

FTP (TCP) - 21
SSH (TCP) - 22
Telnet (TCP) - 23
HTTP (TCP) - 80

Registered - range 1024 to 49151
Dynamic or private ports - 49152 to 65535

Front 2

X.25 Protocol

Back 2

Network data and physical layer of OSCI
Protocols used LAPB
PLP
Designed to operate over unreliable with physical and data link

Front 3

Frame Relay

Back 3

Forward frames and performs error checks only at end point.
Provides point to point connection by creating virtual circuit paths
Works on physical and data link layers
Operates on more reliable networks then X. 25
Virtual circuits 2 types
SVC - temporary VC for sporadic data transfer regulation and maintains only frame
PVC - permanent virtual connection. dedicated data transfer
Uses packet switched technology
Provides

Front 4

IEEE 802.3

Back 4

Preamble - binary data that informs receive stations that a frame is approaching. Start frame delineate. Sof - 1 byte binary info
Destination address - 6 bytes of
Source address - identity of sender
Length type - the number of the MAC - client data bytes presents

Data - 1500 bytes of information
Frame check sequence - 4 byte sequence used for cyclic redundancy check and missed frame detection

Front 5

Packet Switched Networks

Back 5

X.25 uses carrier switches that enable computers on different public networks to communicate. DTE and DCE
LAPB - Link access procedure balance. works with X.25. Retransmits, exchanges and acknowledges frames. Ensures frames are correctly sequenced and error free.
Frame Relay - upgrade from X.25 forward packets to destination without pinpacking at each node. Results in increased speed. Operates at physical and data link.
SMD5 - high speed data gram connectionless protocol
ATM - asynchronous transfer mode. Fixed cell size 53 bytes. High speed connection oriented use cell.

Front 6

Remote Access Protocols

Back 6

SLIP - serial line internet protoase. Encapsulates IP packet by apending special frames character. Only frames defines two special channels. end oct al 300 and ESC octal 333
PPP - point to point - serial link connection standard for assigning IP. Supports DEC net and IP exchange. Asynchronous and synchronous and process network protocol multiplexing. Callback, demand delay, scripting, multi link and filtering. Header compression, server routing, tunneling, extra encapsulation
CHAP - challenge handshake authentication protocol 1. Challenge to peer 2. has value 3. authenticator verifies sent value and acknowledge or based on the
PAP -password authentication protocol. Enable authentication over PPP ( 2 way handshake) 1. user puts in username and password. 2. link est credential send to authentication 3. authenticator verifies and creates or terminates not secure. Send credential through clear text
EAP - extensible authenticated protocol. framework that supports multiple authentication. Functions at data link.

Front 7

SSH

Back 7

Secure Shell (22)- protocol used to log on over network execute commands on remote computer and to move files from 1 computer to another.
The user decrypts the message sent by the host with public key
Secure tunnel between 2 computers. uses TCP 22.
The user authenticates host by encrypting a message with user public key.
Strong authentication and secure
Uses RSA for certificate exchange and 3 DES for session encryption.
Protects against: IP spoofing, spoofer on local network, IP source routing, DNS spoofing, interception data, man in middle, and session highacking

Front 8

SSL

Back 8

Secure Socket Layer - transport layer - provides privacy and reliability between two computer applications. 2 layers structure. encrypts data transmitted.

SSL - record protocol layer - is the lower layer. Layered on TCP and ensures data security and integrity
RC4 - 40 bits
SSL handshake - establishes SSL connection includes server and client mutual authentication and negotiation of an encryption algorithm and keys before the application protocol transmits.
Security features: Privacy (DES or RC4): reliability (MAC, MD5 or SHA)

Front 9

TLS Protocol

Back 9

IETF developed based on SSL 3.0. developed to provide standard for secure transmission over the world wide web.
Goal provide privacy and integrity. Provides HTTS for internet.
HTTPs encrypts data credential before transmistion
2 Layers - tLS handshake protocol layer establishes connection includes server and client mutual authentication and negotiatio of an encryption algorithm and keys. Authentication secure negotration of share secret and reliable.
TLS record layer - Lower layer on TCP. Connection symmetric encryption privacy reliable transport include MAC

Front 10

Communication Types

Back 10

Asynchronous - Sender can send data at anytime parity bit used randomly to provide error protection. Low transmission rates. Each character is delentaed with the use of a start and stop bit

Synchronous data - is transmitted in a stream of bits. Uses control bits only at the start and end of the entire transmission. Has low overhead. Communication takes place between two devices using clock.

Front 11

Network Layer Protocols

Back 11

IPsec - group forms extend to IP. Works at the network layer. Open, modular. Used to set up multiple simultaneous tunnels. Strong encryption and authentication 2 modes. 1 tunnel modes - payload and routing and header information for a packet are encrypted. 2. transport mode - payload is encrypted uses AH protocol, 96 bits long and forms a has of authentication token.
ESP protocol - authentication and encryption and confidentiality uses 3DES or IKE for key exchange. Creates secure tunnels through unsecured networks.
L2TP - Cisco L2F and Microsoft PTP. Strong authentication support multiple VPN protocols and unregistered and private IP and over multiple networks. Enable secure transport over multinetworks.
PPTP - individual client server connection to local ISP. Then secure VPN. Over IP networks only. Uses MS CHAP. Low cost connection via internet.
SKIP - siimple key management for IP provides security, authentication and registration. Uses Diffie Hellman 1024 bit public key for authentication. Encrypts using DES, RC2 and RC4. Similar to SSL but does not require prior communication. Enables certain of and large VPN beyond LAN and WAN
SWIPE - confidentiality, integrity and authentication. Provides end to end and intermediate hop security doesn't handle policy and key management.

Augments each packet with cryptology strong authenticator.

Front 12

TCP/IP Protocols

Back 12

TCP - host to host transport layer. Transport connection that ensures packets are i the correct format when they reach the destination complete uses 3 way handshake.
UDP - connectionless transport protocol does not guarantee packet ad has reached destination ad uses less resources and faster.
IP - network layer correction less protocol

Front 13

TCP/IP Layers

Back 13

Application layer - top layer interface to user. Converts received data into a user understandable form. (FTP, SNTP, Telnet, HTTP)
Transport Layer - use to transfer data between application controlling data transmission through the network layer. Transfer data between application uses UDP or TCP.
Internet Layer - heart of architecture. Handles the delivery of information from computer to other computers across networks. (ICMP)
Network Access - defines how the physical layer transmits packet between computers. Helps to convert data into bits. (ARP)

Front 14

TCP and UDP

Back 14

Transmission control Protocol
Full duplex connected oriented reliable. Sequenced reliable, high over head, slower
User Datagram Protocol best effort delivery - unsequeced, connectionless, unreliable, low overhead, faster.

Front 15

IEEE Wireless Standards

Back 15

802.11 2.4 Ghz 1 or 2 Mbps
a. 5 Ghz 54 Mbps
b. 2.4 Ghz up to 11 Mbps
g. 2.4 Ghz 20 to 54 Mbps
n. 5 Ghz 100 to 600 Mbps

Front 16

Spanning Tree Protocol

Back 16

Uses the STA to identify the best path to communicate with a node and any alternative path.

Front 17

Email

Back 17

Pretty Good Privacy - Phil Zimmerman 1991 MD5 has IDEA. Uses RSA private ad public. keys. Compresses data prior to encryption. Web of trust. Trust levels (untrusted, marginal complete ad ultimate. For a public key.
Privacy Enhance Mail - PEM, IETF, authorize MD2 ad MD5. Integrity. X.509 encryption (DES). Key management RSA. 7 bit text messages defies hierarchical structure and specification. Public key infrastructure. Highly structured and not compatible with MIME.
Secure MIME -provide secure method to send MIME confidentiality ad itegrity of message. RC2, DES, 3 DES, MD5, SHA, X. 509