Lesson 1

Introduction to Networking Concepts

TCP/IP: The most commonly used network protocol on modern networks is the Transmission Control Protocol/Internet Protocol (TCP/IP) protocol suite. TCP/IP Protocols were developed by the Department of Defense–ARPANET (1960s). Its purpose is to share data/talk to other computes and only share/talk to computers that we trust and want to allow access. TCP/IP is not just one protocol but a collection of specialized protocols/subprotocols. TCP/IP has become the protocol of choice and both Microsoft and NetWare/Novell use it as their default protocol.

IP Versions

IPv4: Addressing Networks recognize two addresses: Logical (Network layer) IP address assigned dynamically or manually, and the Physical (MAC, hardware) address is static, assigned by the manufacture. The IPv4 protocol handles logical addressing. The IP address contains specific parameters (unique 32-bit number, divided into four octets, and separated by periods). Example: 192.168.1.99. The addresses are then further divided in classes. The first octet specifies the network class you are using on your network.

Classes:
A 1-126 00000001 - 01111111 Subnet Mask 255.0.0.0
B 128-191 10000000 - 10111111 Subnet Mask 255.255.0.0
C 192-223 11000000- 11011111 Subnet Mask 255.255.255.0
D 224-230 11100000-11101111 Reserved for Multi Casting Video Conferencing
E 240-254 11110000-11110111 Testing and Research

IPv6: Addressing is the next generation of IP addressing that is gradually replacing IPv4. IPv6 uses 128 bits, or 16 bytes, for addressing, thus providing 2128 (about 340 billion) unique addresses. Most new development of applications, servers, and network devices support it. Advantages are a more efficient header, better security, better prioritization provisions, automatic IP address configuration, and it also adds billions of additional IP addresses. IPv6 enhances security through the use of IPSec, where as in IPv4 it is an optional feature.

DNS (Domain Name System): TCP/IP addressing is made up of numbers which are not easily remembered by most humans. Therefore a naming system was established. Which takes the host/device or domain IP address and gives it a common name such as Host Name “SERVER” or Domain Name “procomps.com”. The DNS (Domain Name System) relies on many computers across the globe. These computers are related in hierarchical and distributed manners, with 13 computers, known as root servers, so DNS will not fail if there are a handful of the servers experiencing errors. Thus, when changing your DNS for a mail server, it can take up to 24 hours for all DNS servers in the system to update. Reasons to use DNS for its scalability, transparency ease of use and simplicity. The components of DNS are namespace, zones, name servers and resource records.



Dynamic Host Configuration Protocol (DHCP): Each host on a TCP/IP network needs to be configured with a unique IP address. Network administrators can use the Dynamic Host Configuration Protocol (DHCP) to automatically assign IP addresses to multiple client computers. 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. Clients may also be configured to use APIPA or an alternate static IP address configuration if DHCP is unavailable. To support and use the DHCP service across multiple subnets, routers connecting each subnet should comply with the DHCP/BOOTP relay agent capabilities described in RFC 1542.

Five Benefits of DHCP:
• Centralized administration of IP configuration
• Dynamic host configuration
• Seamless IP host configuration
• Scalability
• Flexibility

DHCP relay agents eliminate the need to have a DHCP server on every subnet. The DHCP relay agent listens for DHCPDISCOVER, DHCPREQUEST and DHCPINFORM which messages that are broadcast from the client?

Using the Routing and Remote Access Service: 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. This routing service included with Windows Server 2008 is better suited for a smaller networks.

Network Access Protection (NAP)
Network Access Protection (NAP) is a new feature in Windows Server 2008. NAP allows administrators to enforce network security policies, such as mandatory anti-virus or firewall configuration.