MTA Network Fundamental Cram Sesion Mark Rawlings

Network Topology A network topology defines the physical connections of hosts in a computer network. There are several types of physical topologies including: Bus Ring Star Mesh Tree

Star Topology Most Common topology Each computer is individually wired to a central connecting device (hub, switch or SOHO router) with twisted-pair cabling.

Mesh Topology Every computer connects to every other computer; no central connecting device is needed.

Ring Topology In a LAN environment, each computer is connected to the network using a closed loop. Used by Token Ring and FDDI.

Token Ring A Token Ring network sends data logically in a ring fashion, meaning that a token goes to each computer, one at a time, and continues on in cycles. However, Token Ring computers are physically connected in a star fashion. Namely, all computers in a Token Ring network are connected to a central connecting device known as a Multistation Access Unit (MAU or MSAU).

Ethernet Ethernet is a group of networking technologies that define how information is sent and received between network adapters, hubs, switches, and other devices. Ethernet is the de facto standard and has the largest share of networks in place today. Ethernet is standardized by the Institute of Electrical and Electronics Engineers (IEEE) as 802.3.

Ports

Ports It is important to understand the difference between inbound and outbound ports: Inbound ports Outbound ports

Ports

NetStat Command This will display a list of all the connections to and from your computer in numeric format

OSI Model Revisited

WLAN Standards

Wireless Encryption Options

Classful Network Architecture

Loopback Testing The range for Class A is 0–127. The 127 network number isn’t used by hosts as a logical IP address. Instead, this network is used for loopback IP addresses, which allow for testing.

Private Addresses

APIPA APIPA is an acronym for Automatic Private IP Addressing. It uses a single Class B network number: 169.254.0.0. If a Windows client cannot get an IP address from a DHCP server and has not been configured statically, it will auto-assign a number on this network.

IPConfig Command Displays IP Configuration

IPConfig /All Command

IPConfig /Release

Ping Command Used to test network connectivity Users ICMP

Tracert Command W

PathPing Command

NetStat Command

NSLookup Nslookup displays information about DNS names and their corresponding IP addresses, and it can be used to diagnose DNS servers.

IPSec Internet Protocol Security (IPSec) is a protocol within the TCP/IP suite that encrypts and authenticates IP packets. It is designed to secure any application traffic because it resides on the network layer (or Internet layer, as TCP/IP programmers refer to it). This protocol is used in conjunction with virtual private networks and is an integral part of IPv6.

WINS Windows Internet Name Service (WINS) is a service that resolves NetBIOS names to IP addresses. It is Microsoft’s version of the NetBIOS Name Service (NBNS) combined with a name server.

T-Carriers The two most common T-carrier systems are as follows: T1: It is considered 1.544 Mbps, but only 1.536 Mbps of that is for data. The 1.536 Mbps is broken into 24 equal 64 Kbps channels and can be used with a multiplexor. T3: Stands for trunk Carrier 3. Equivalent of 28 T1s. It is considered 44.736 Mbps, using 672 64 Kbps B channels.

DSL Digital subscriber line (DSL) is a family of technologies that provides data transmissions over local telephone networks. xDSL is the standard for the various digital subscriber lines. ADSL (asymmetrical digital subscriber lines) can run on your home telephone line so that you can talk on the phone and access the Internet at the same time. SDSL (symmetrical digital subscriber line) is installed (usually to companies) as a separate line and is more expensive. The upload and download speed are the same or symmetrical.

VPN Popular VPN Protocols are: PPTP: generally includes security mechanisms, and no additional software or protocols need to be loaded. L2TP with IPSec: L2TP not normally encrypted – IP Sec added for encryption Site to Site VPN: Establishes a secure connection over public web SSL VPN: Used with standard web browser – no install needed

Point-to-Point Tunneling Protocol Point-to-Point Tunneling Protocol (PPTP) is the more commonly used protocol, but it is also the less secure option. PPTP generally includes security mechanisms, and no additional software or protocols need to be loaded. A VPN device or server that allows incoming PPTP connections must have inbound port 1723 open. PPTP works within the point-to-point protocol (PPP), which is also used for dial-up connections.

L2TP with IPSec Layer 2 Tunneling Protocol (L2TP) is quickly gaining popularity due to the inclusion of IPsec as its security protocol. Although this is a separate protocol and L2TP doesn’t have any inherent security, L2TP is considered the more secure solution because IPsec is required in most L2TP implementations. A VPN device or server that allows incoming L2TP connections must have inbound port 1701 open.

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