Introduction to Networking Concepts

Introducing TCP/IP Addressing

 Network address – common portion of the IP address shared by all hosts on a subnet/network.

 Host address – the part of the IP address the uniquely identifies each host on a network  The Network and Host parts of the address are determined by the subnet mask.

 Default Gateway – a way out of our network. Allows us to communicate outside the LAN.

IPv4 vs IPv6

 IPv4 uses a 32 bit address and subnet mask – sometimes broken down into legacy “classes of networks” (page 4)  IPv4 addresses are running out – techniques such as Private IP addresses are being used along with NAT to help save some addresses. (page 5)  IPv6 uses 128 bit. Provides up to 2^128 unique addresses. 20AB:0db8:85d3:1218:8a2e:0370:7334 is an exaple of an IPv6 address  IPv6 address use a 48 bit subnet mask.

Introduction to DNS

 DNS – provides a mechanism for associating meaninful host names with network address.  It is easier to remember names than numbers.

 DNS plays a strong role in Server and Internet functionality.

 DNS is the main name resolution technique used in todays networks. Previous to this was the HOSTS file.

 Show hosts file

DNS benefits

 Scalable – capable of adding mutliples names to the database without affecting performance. Distributes workload among DNS servers.

 Transparency – Host names remain constant even when associated IP address change.

 Ease of Use – Use names to access resources instead of numerical IP addresses.

 Simplicity – Users need to learn only one naming convention to find resources on the Internet.

DNS namespace

 Hierarchical – tree structure page 7.

Intro to DHCP

 DHCP – Dynamic Host Configuration Protocol  Automatically assigns IP address to Hosts on the network

Benefits of DHCP

 Centralized administration  Dynamic host config –elimates need for manually entering IP addresses  Seamless IP host config – no user intervention  Scalability – scales from small to large networks. Can add almost unlimited number of hosts.

 Flexibility – Can easily change IP configurations when the infrastructure changes.

DHCP Relay Agent

 DHCP uses broadcast messages – routers block broadcast messages so a relay agent must be used in between network segments.

Configuring clients without DHCP

 Automatic Private IP addressing (APIPA) – Windows machines that can not find a DHCP server will then be given an APIPA address. 169.254.X.X

 Alternate Configuration – can be used when clients connect to a network that does not offer DHCP.

Routing and Remote Access RRAS

 RRAS can allow us to use our Windows Server sytem as a Router if we do not have one.

 RRAS can allow clients to connect remotely to the server as if they were on the network. VPN is an example of this.

Network Access Protection NAP

 Feature that allows network admins to specify policies that define who has access to the network.

 Similar to BSC’s protection on Lab PC’s  For example if a computer is brought in that has no Antivirus it will be put in a quarantined section so it can’t affect other clients on the network.

You Learned

 Network protocols create a logical language that allows computers to communicate.

 The most commonly used network protocol on modern networks is the Transmission Control Protocol/Internet Protocol (TCP/IP) protocol suite.

 There are currently two implementations of TCP/IP: TCP/IP version 4, or IPv4, and TCP/IP version 6, or IPv6.

You Learned

(cont.)

 Each host on a TCP/IP network needs to be configured with a unique IP address.

 TCP/IP networks use the Domain Name System (DNS) to map human-readable machine names to IP addresses and vice versa, such as mapping the www.cpandl.com host name to the 10.10.1.104 IP address.

Lesson 1

You Learned

(cont.)

 DNS provides name resolution to allow meaningful names to be used to refer to network addresses.

 DHCP is a simple, standard protocol that makes TCP/IP network configuration much easier for the administrator by dynamically assigning IP addresses and providing additional configuration information to DHCP clients automatically.

Lesson 1

You Learned

(cont.)

 Network administrators can use the Dynamic Host Configuration Protocol (DHCP) to automatically assign IP addresses to multiple client computers.

 Clients may be configured to use APIPA or an alternate static IP address configuration if DHCP is unavailable.

You Learned

(cont.)

 The Routing and Remote Access service provides the ability to use a Windows Server 2008 computer as a router, which passes network traffic from one TCP/IP network to another, as well as remote access capabilities using either dial-up or VPN technology

You Learned

(cont.)

 To allow administrators to enforce network security policies, such as mandatory anti-virus or firewall configurations, Windows Server 2008 has introduced the Network Access Protection (NAP) enforcement platform.