What is IPV6.....

IPv6 Addresses

IPv6 (Internet Protocol version 6 ) is the next generation of the Internet Protocol after IPv4. It provides an expanded address space, a simplified header format, improved support for extensions and options, flow labeling capability, and authentication and privacy capabilities. IPv6 is described in RFC 2460. The IPv6 addressing architecture is described in RFC 3513.

This section describes the IPv6 address format and architecture and includes the following topics:

• IPv6 Address Format

• IPv6 Address Types

• IPv6 Address Prefixes

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Note :This section describes the IPv6 address format, the types, and prefixes. For information about configuring the adaptive security appliance to use IPv6

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IPv6 Address Format

IPv6 addresses are represented as a series of eight 16-bit hexadecimal fields separated by colons (:) in the format: x:x:x:x:x:x:x:x. The following are two examples of IPv6 addresses:

• 2001:0DB8:7654:3210:FEDC:BA98:7654:3210

• 2001:0DB8:0000:0000:0008:0800:200C:417A

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Note: The hexadecimal letters in IPv6 addresses are not case-sensitive.

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It is not necessary to include the leading zeros in an individual field of the address. But each field must contain at least one digit. So the example address 2001:0DB8:0000:0000:0008:0800:200C:417A can be shortened to 2001:0DB8:0:0:8:800:200C:417A by removing the leading zeros from the third through sixth fields from the left. The fields that contained all zeros (the third and fourth fields from the left) were shortened to a single zero. The fifth field from the left had the three leading zeros removed, leaving a single 8 in that field, and the sixth field from the left had the one leading zero removed, leaving 800 in that field.

It is common for IPv6 addresses to contain several consecutive hexadecimal fields of zeros. You can use two colons (::) to compress consecutive fields of zeros at the beginning, middle, or end of an IPv6 address (the colons represent the successive hexadecimal fields of zeros). Table D-2 shows several examples of address compression for different types of IPv6 address.

Address Type	Standard Form	Compressed Form
Unicast	2001:0DB8:0:0:0:BA98:0:3210	2001:0DB8::BA98:0:3210
Multicast	FF01:0:0:0:0:0:0:101	FF01::101
Loopback	0:0:0:0:0:0:0:1	::1
Unspecified	0:0:0:0:0:0:0:0	::

Note Two colons (::) can be used only once in an IPv6 address to represent successive fields of zeros.

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An alternative form of the IPv6 format is often used when dealing with an environment that contains both IPv4 and IPv6 addresses. This alternative has the format x:x:x:x:x:x:y.y.y.y, where x represent the hexadecimal values for the six high-order parts of the IPv6 address and y represent decimal values for the 32-bit IPv4 part of the address (which takes the place of the remaining two 16-bit parts of the IPv6 address). For example, the IPv4 address 192.168.1.1 could be represented as the IPv6 address 0:0:0:0:0:0:FFFF:192.168.1.1, or ::FFFF:192.168.1.1.

IPv6 Address Types

The following are the three main types of IPv6 addresses:

• Unicast—A unicast address is an identifier for a single interface. A packet sent to a unicast address is delivered to the interface identified by that address. An interface may have more than one unicast address assigned to it.

• Multicast—A multicast address is an identifier for a set of interfaces. A packet sent to a multicast address is delivered to all addresses identified by that address.

• Anycast—An anycast address is an identifier for a set of interfaces. Unlike a multicast address, a packet sent to an anycast address is only delivered to the "nearest" interface, as determined by the measure of distances for the routing protocol.

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Note There are no broadcast addresses in

• Unicast Addresses

• Multicast Address

• Anycast Address

• Required Addresses

Unicast Addresses

This section describes IPv6 unicast addresses. Unicast addresses identify an interface on a network node.

This section includes the following topics:

• Global Address

• Site-Local Address

• Link-Local Address

• IPv4-Compatible IPv6 Addresses

• Unspecified Address

• Loopback Address

• Interface Identifiers

Global Address

The general format of an IPv6 global unicast address is a global routing prefix followed by a subnet ID followed by an interface ID. The global routing prefix can be any prefix not reserved by another IPv6 address type (see IPv6 Address Prefixes, for information about the IPv6 address type prefixes).

All global unicast addresses, other than those that start with binary 000, have a 64-bit interface ID in the Modified EUI-64 format. See Interface Identifiers, for more information about the Modified EUI-64 format for interface identifiers.

Global unicast address that start with the binary 000 do not have any constraints on the size or structure of the interface ID portion of the address. One example of this type of address is an IPv6 address with an embedded IPv4 address (see IPv4-Compatible IPv6 Addresses).

Site-Local Address

Site-local addresses are used for addressing within a site. They can be use to address an entire site without using a globally unique prefix. Site-local addresses have the prefix FEC0::/10, followed by a 54-bit subnet ID, and end with a 64-bit interface ID in the modified EUI-64 format.

Site-local Routers do not forward any packets that have a site-local address for a source or destination outside of the site. Therefore, site-local addresses can be considered private addresses.

Link-Local Address

All interfaces are required to have at least one link-local address. You can configure multiple IPv6 addresses per interfaces, but only one link-local address.

A link-local address is an IPv6 unicast address that can be automatically configured on any interface using the link-local prefix FE80::/10 and the interface identifier in modified EUI-64 format. Link-local addresses are used in the neighbor discovery protocol and the stateless autoconfiguration process. Nodes with a link-local address can communicate; they do not need a site-local or globally unique address to communicate.

Routers do not forward any packets that have a link-local address for a source or destination. Therefore, link-local addresses can be considered private addresses.

IPv4-Compatible IPv6 Addresses

There are two types of IPv6 addresses that can contain IPv4 addresses.

The first type is the "IPv4-compatibly IPv6 address." The IPv6 transition mechanisms include a technique for hosts and routers to dynamically tunnel IPv6 packets over IPv4 routing infrastructure. IPv6 nodes that use this technique are assigned special IPv6 unicast addresses that carry a global IPv4 address in the low-order 32 bits. This type of address is termed an "IPv4-compatible IPv6 address" and has the format ::y.y.y.y, where y.y.y.y is an IPv4 unicast address.

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The second type of IPv6 address which holds an embedded IPv4 address is called the "IPv4-mapped IPv6 address." This address type is used to represent the addresses of IPv4 nodes as IPv6 addresses. This type of address has the format ::FFFF:y.y.y.y, where y.y.y.y is an IPv4 unicast address.

Unspecified Address

The unspecified address, 0:0:0:0:0:0:0:0, indicates the absence of an IPv6 address. For example, a newly initialized node on an IPv6 network may use the unspecified address as the source address in its packets until it receives its IPv6 address.

Loopback Address

The loopback address, 0:0:0:0:0:0:0:1, may be used by a node to send an IPv6 packet to itself. The loopback address in IPv6 functions the same as the loopback address in IPv4 (127.0.0.1).

Interface Identifiers

Interface identifiers in IPv6 unicast addresses are used to identify the interfaces on a link. They need to be unique within a subnet prefix. In many cases, the interface identifier is derived from the interface link-layer address. The same interface identifier may be used on multiple interfaces of a single node, as long as those interfaces are attached to different subnets.

For all unicast addresses, except those that start with the binary 000, the interface identifier is required to be 64 bits long and to be constructed in the Modified EUI-64 format. The Modified EUI-64 format is created from the 48-bit MAC address by inverting the universal/local bit in the address and by inserting the hexadecimal number FFFE between the upper three bytes and lower three bytes of the of the MAC address.

For example, and interface with the MAC address of 00E0.b601.3B7A would have a 64-bit interface ID of 02E0:B6FF:FE01:3B7A.

Multicast Address

An IPv6 multicast address is an identifier for a group of interfaces, typically on different nodes. A packet sent to a multicast address is delivered to all interfaces identified by the multicast address. An interface may belong to any number of multicast groups.

An IPv6 multicast address has a prefix of FF00::/8 (1111 1111). The octet following the prefix defines the type and scope of the multicast address. A permanently assigned ("well known") multicast address has a flag parameter equal to 0; a temporary ("transient") multicast address has a flag parameter equal to 1. A multicast address that has the scope of a node, link, site, or organization, or a global scope has a scope parameter of 1, 2, 5, 8, or E, respectively. For example, a multicast address with the prefix FF02::/16 is a permanent multicast address with a link scope. Figure D-1 shows the format of the IPv6 multicast address.

Figure D-1 IPv6 Multicast Address Format

IPv6 nodes (hosts and routers) are required to join the following multicast groups:

• The All Nodes multicast addresses:

– FF01:: (interface-local)

– FF02:: (link-local)

• The Solicited-Node Address for each IPv6 unicast and anycast address on the node: FF02:0:0:0:0:1:FFXX:XXXX/104, where XX:XXXX is the low-order 24-bits of the unicast or anycast address.

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IPv6 routers are required to join the following multicast groups:

• FF01::2 (interface-local)

• FF02::2 (link-local)

• FF05::2 (site-local)

Multicast address should not be used as source addresses in IPv6 packets.

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Anycast Address

The IPv6 anycast address is a unicast address that is assigned to more than one interface (typically belonging to different nodes). A packet that is routed to an anycast address is routed to the nearest interface having that address, the nearness being determined by the routing protocol in effect.

Anycast addresses are allocated from the unicast address space. An anycast address is simply a unicast address that has been assigned to more than one interface, and the interfaces must be configured to recognize the address as an anycast address.

The following restrictions apply to anycast addresses:

• An anycast address cannot be used as the source address for an IPv6 packet.

• An anycast address cannot be assigned to an IPv6 host; it can only be assigned to an IPv6 router.

Required Addresses

IPv6 hosts must, at a minimum, be configured with the following addresses (either automatically or manually):

• A link-local address for each interface.

• The loopback address.

• The All-Nodes multicast addresses

• A Solicited-Node multicast address for each unicast or anycast address.

IPv6 routers must, at a minimum, be configured with the following addresses (either automatically or manually):

• The required host addresses.

• The Subnet-Router anycast addresses for all interfaces for which it is configured to act as a router.

• The All-Routers multicast addresses.

IPv6 Address Prefixes

An IPv6 address prefix, in the format ipv6-prefix/prefix-length, can be used to represent bit-wise contiguous blocks of the entire address space. The IPv6-prefix must be in the form documented in RFC 2373 where the address is specified in hexadecimal using 16-bit values between colons. The prefix length is a decimal value that indicates how many of the high-order contiguous bits of the address comprise the prefix (the network portion of the address). For example, 2001:0DB8:8086:6502::/32 is a valid IPv6 prefix.

The IPv6 prefix identifies the type of IPv6 address. Table D-3 shows the prefixes for each IPv6 address type.

Table D-3 IPv6 Address Type Prefixes
Address Type	Binary Prefix	IPv6 Notation
Unspecified	000...0 (128 bits)	::/128
Loopback	000...1 (128 bits)	::1/128
Multicast	11111111	FF00::/8
Link-Local (unicast)	1111111010	FE80::/10
Site-Local (unicast)	1111111111	FEC0::/10
Global (unicast)	All other addresses.
Anycast	Taken from the unicast address space.

                        Difference Between IPV4 & IPV6 

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Windows 7: Virtual Hard Disk - Create and Attach VHD

            Step by Step Configuration of VHD

Here's How:

1. Open the Control Panel (icons view).

A) Click on the Administrative Tools icon, and click on Computer Management.

B) Go to step 3.

OR

2. Open the Start Menu.

A) In the Search box, type compmgmt.msc and press Enter.

3. If prompted by UAC, click on Yes, then do either step 4 or 5 below.

4. To Attach an Existing VHD File
NOTE: This is for a detached VHD file that you had already created in step 5 below, or from an existing VHD file.

A) In the left pane, right click on Disk Management, and click on Attach VHD
NOTE: You can also click on Disk Management, Action on the menu bar, and Attach VHD.

B) Click on the Browse button

C) Navigate to the VHD file location and select it, then click on the Open button.

D) If you want the VHD to be read-only, then check the box, otherwise leave it unchecked. Click on OK.

E) If the existing VHD file is unallocated, go to step 6.
WARNING: Be sure to create a backup copy of the VHD file first to be safe in case of data loss.

F) If the existing VHD file is allocated, go to step 8.

5. To Create and Attach a New Virtual Hard Disk (VHD file)

A) In the left pane, right click on Disk Management, and click on Create VHD.
NOTE: You can also click on Disk Management, Action on the menu bar, and Create VHD.

B) Click on the Browse button

C) Navigate to the location you would like to store the new VHD file, type in a name for the VHD file, and click on Save

.

D) Type in the maximum size you want the Virtual Hard Disk to be, and select the size to be MB, GB, or TB (1024 MB = 1 GB, 1024 GB = 1 TB).

E) Select (dot) if you want the new VHD size to be Dynamic or Fixed, and click on OK

F) Continue to step 6.

6. To Initialize the Virtual Hard Disk

A) Right click on the new unallocated VHD Disk # and click on Initialize Disk

B) Select (check) the Disk # from above for the new VHD. Select (dot) if you want the new VHD to have a MBR (Master Boot Record) or GPT (GUID Partition Table) partition, and click on OK

C) Continue to step 7.

7. To Create a New Simple Volume in the VHD

A) Right click on the new unallocated VHD and click on New Simple Volume.

B) Click on the Next button.

C) Type in how much of the maximum disk space (step 5D) you want for the size of this VHD partition, and click on Next.

NOTE: If you do not use the maximum space, then you will have a second unallocated VHD partition left with the remaining available disk space

D) Select the file system (NTFS or FAT32) you want the VHD partition to be.

E) Type in a name for the VHD to be displayed in Computer.

F) Check the Perform a quick format box, and click on Next.

G) Click on the Finish button

8. The VHD is now attached and ready to access like a HDD.

That's it

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