Network Services

 IPv4 configuration and operation depends upon the number of network services. On a small network DHCP (Dynamic Host Configuration Protocol) and DNS (Domain Name Server) services can be provided by a client running ICS (Internet Connection Sharing).

Services associated with IPv4 include the following:

DHCP: Dynamic Host Configuration Protocol assigns IPv4 addresses to hosts that are set to receive their configurations automatically. DHCP can also specify the IPv4 address of the default gateway(s) and DNS server(s)

DNS: Domain Name Server resolves the local host names to IP address as well as resolves IP address to local host names

APIPA: Automatic private IP addressing configures an internal private network when DHCP is not provided

NAT: Network Address Translation allows many devices on a private network to gain access to the Internet through one public IPv4 address. NAT translates between private IPv4 addresses used internally in local network and public addresses used on the internet.

Connecting to a Network:

An intranet is the generic term for a collection of private computer networks within an organization. The internet is an open international network that is available to everyone.

Most networks are connected to the intranet or internet; these networks are connected either directly or with the help of network devices. Computers are connected to the intranet or internet with the help of static or dynamic IP address.

Workgroup

A workgroup is a set of the computer which belongs to same network and does not have any centralized controllers. All the computers in workgroup are in peer to peer network. Each computer has a set of user accounts. To log on to any computer in the workgroup, you must have an account on that computer. All computers must be on the same local network or subnet 

Troubleshooting Network Connectivity

Basic Troubleshooting

There are various problems you may face in your computer. In wired networks, the cable used might be faulty or connecting socket is not working properly.

Troubleshooting IP Configuration

For troubleshooting the IP configuration you can use the command-line tools. You can use the ipconfig /all command for all the configuration information for all interfaces

Checking Computer to Computer Connectivity

With the help of windows 7 you can check computer to computer connectivity. To connect to other computer on a LAN, Network Discovery needs to be enabled on both source and destination computers

Windows Network Diagnostics Tool

Windows 7 provides you with the automated assistance with the Windows Network Diagnostic tool. The Web page that appears in your browser gives you a direct link to the tool when you click Diagnose Connection Problems

Network Settings in Windows Firewall

In Windows 7, Windows firewall is enabled by default. With the help of Window Firewall you can block all incoming traffic of packets. You can allow a program through the firewall by opening one or more ports. Windows Firewall allows Core Networking Components by default in both public and private networks.

Analyzing the IPv6 Address Structure

IPv4 and IPv6 addresses can be easily identified. An IPv4 address uses 32 bits whereas IPv6 address 128 bits

IPv6 provides address that is similar to IPv4 and other unique address to IPv6

IPv6 Address Syntax:

IPv6 128-bit address is divided into 16-bit boundaries and each 16-bit block is converted to a 4-digit hexadecimal number. Colons are used as separators. This representation is known as colon-hexadecimal

 Analyzing the IPv6 Address Structure

IPv6 Address Prefixes:

nThe prefix is the part of the address that indicates either the bits that have fixed values or the network identifier bits. IPv6 address prefix is a combination of an IPv6 prefix and prefix length

nIPv6 Address Types:

nThere are three types of IPv6 address :

nUnicast: Unicast is used to identify a single interface within the scope of the unicast address type. Packet sent to a unicast address is delivered to a single interface.

Analyzing the IPv6 Address Structure

nAnycast: An identifier is used for multiple interfaces. A packet sent to an anycast address is delivered to nearest interfaces identified by that address. The nearest interface is the closet in terms of routing distance

nMulticast: An identifier is used for a set of interfaces. A packet addressed to a multicast address is delivered to all interfaces identified by that address

Advantages of IPv6

The main advantages of IPv6 are as follows:

nIncreased address space: IPv6 provides addresses for every device which needs to have a unique public IPv6 address. In Ipv6, 64-bit host portion address can be automatically generated from the network adapter hardware

nAutomatic Address Configuration: IPv6 deals with the need for simpler and more automatic address configuration by supporting both stateful and stateless address configuration

Advantages of IPv6 – I

Network Level Security: Communication over the internet requires encryption to protect data from being viewed or modified in transit. Internet Protocol Security (IPsec) provides this facility and IPv6 makes IPsec mandatory

nReal-time data delivery: Quality of Service (QoS) exists in IPv4, and bandwidth can be guaranteed for real-time traffic over a network. Payload identification is included in the Flow Label field of the IPv6 header, so payload encryption does not affect QoS operation

Routing table size: On the IPv6 Internet, backbone routers have greatly reduced routing tables that use route aggregation which permits a number of contiguous address blocks to be combined and summarized into a larger address block.

nHeader size and extension headers: IPv6 header is smaller in size as compared to IPV4. The optional field are moved to extenstion headers in IPv6

nRemoval of Broadcast traffic: IPv6 Neighbor Discovery (ND) protocol uses a series of ICMPv6 messages

Implementing IPv4 to IPv6 Compatibility

IPv6 provides the type of compatibility addresses from IPv4 to IPv6 and to implement transition technologies

nIPv4-Compatible Address

nIPv4 compatible address is derived from IPv4 public address and it provides a method of connecting IPv6 hosts over the IPv4 Internet Infrastructure

IPv4 Mapped Address

nThese addresses are commonly represented in the standard IPv6 format, but have the last 32 bits written in the customary dot decimal notation of IPv4

n6 to 4 Address

n6 to 4 helps you to enable IPv6 packets to be transmitted on the IPv4 network without explicit tunnels. 6 to 4 hosts can communicate with hosts on the IPv6 Internet. It is used when user wants to connect to IPv6 network using the existing IPv4 connection

You can implement IPv6 to IPv4 compatibility by using the IPv6 tools Netsh interface ipv6 6to4, Netsh interface ipv6 isatap, and Netsh interface ipv6 add v6v4tunnel

nSuppose you want to create an IPv6 to Ipv4 tunnel between the local address 10.0.0.11 and the remote address 192.168.123.116 on an interface named remote, you would enter netsh interface ipv6 add v6v4tunnel “Remote” 10.0.0.11 192.168.123.116

Configuring IPv6 Connectivity

In Windows 7 to check the functionality of the IPv6 you can use the command-line tools such as Ping, Ipconfig, Pathping, Traceret, Netstat and Route

nTools required for the IPv6 are provided in the Netsh structure