A New IP Version is : IPv6

 

First Q Really We need a IP Version?

Ans- the answer is: “YES”

Because;

Living in a world where nearly every household has more than one computer, imagine the number of IP addresses required for them. Likewise, more and more IP telephones and IP television sets are being introduced around the world, ensuring that the public IP address range will eventually be exhausted. The Network Address Translator (NAT) has been implemented to provide a temporary solution to the scarce number of IP addresses.

The new version of IP is IPv6 which is  more flexible, scalable, and adaptable to the growth and changes of the Internet.

The benefits from IPv6 are huge. IPv6 is able accomplish :

1. It makes NAT and its drawbacks obsolete
2. It covers the IP addressing needs of every IP device on the planet
3. It’s ideal for supporting new generation services
4. Supports mobility
5. Provides security
6. Serves in the greater extend the strict quality requirements of broadband services.

Note : The transformation to IPv6 will not be completed overnight. It will take some years during which coexistence of IPv4 and IPv6 will be common, however IPv6 will eventually dominate and Although it’s a new technology, it is expected to grow exponentially and eventually completely replace IPv4.

Here’s what IPv6 has to offer:

• Billions of addresses with no possibility of exhaustion
• Ability to lighten the burden of huge routing tables
• Provide extra security features
• Simplify the routing process
• Allow efficient and accurate Quality of Service options
• Support possible future evolution
• Provide interoperability between old and new version

 Main Features and Improvements in IPv6 compare to IPv6 :

• Simpler Header Format – IPv6 contains only eight fields, compared to fourteen fields in IPv4, making its processing faster and consequently improving throughput.
• Longer Address Space – Source and destination addresses are sixteen bytes long each, versus four bytes in IPv4, which eliminates the shortage on IP addressing space.
• Hierarchical Addressing Scheme – IPv6 provides a more efficient addressing scheme which decreases the huge number of routing entries in backbone routers with its efficient summarization capability.
• Built-in Security – Data integrity and authentication are assured in IPv6 with the use of IPSec.
• Better QoS support – A completely new 20-bit field in the IPv6 header is used to identify different traffic flows between a source and destination, and apply the necessary policies appropriately.
• Extensibility – At the end of the IPv6 header, various extended options can be supported, making it possible for extensions to be easily adaptable.

 

About IPv6 Addresses :

IPv6 addresses are written in eight groups of four hexadecimal digits with colons separating each group like so:

• 2000:0000:0000:0000:0457:ACFD:45CB:230B

First leading zeros within a group can be omitted. For example 0457 can be written as 457. Also, successive groups of zero bits can be replaced by a pair of colons as “::”. This substitution can only take place one time in an address. Using the above example: 2000:0000:0000:0000:0457:ACFD:45CB:230B can be replaced with:2000::457:ACFD:45CB:230B.

In a compressed IPv6 address representation, to be able to resolve its fully qualified representation, you can count the number of groups in the compressed address, subtract this number from 8, and then multiply the result by 16. The result will be the number of bits represented by the “::”.

For example, in the address 2000::457:ACFD:45CB:230B, there are five blocks. The number of bits expressed by the “::” is 48 or (8 – 5) x 16. Each group is represented by 16 bits, hence 3 (48/16) groups of leading “zeros” are represented by the “::”.

The difference IPv6 address types include:

• Unicast – one-to-one
• Multicast – one-to-many
• Anycast – one-to-nearest

Note: Broadcast address scheme is not defined in IPv6; broadcasting as known in IPv4 is performed using multicast address in IPv6.

Unicast address type is the most common IP address type that is assigned to individual interfaces. It is divided into various types of unicast addresses according to their purpose. The most important ones are: IPv6 Global Unicast Addresses, Link-Local Addresses, and Special Addresses. Details about these addresses can be found in RFC 2373.

IPv6 Global Unicast Addresses are also known as Aggregatable Global Unicast Addresses, identified by the Format Prefix of 2000::/3 through E000::/3, with the exception of FF00::/8. These addresses are equivalent to public IPv4 addresses. By default, the number of bits used to identify the subnet is 64 and the number of bits used to identify the host on the subnet is again 64. At the ISP, or organization boundaries, these addresses can be aggregated hence limiting routing table entries.

The 64-bit host identifier in an IPv6 address is derived from the underlying link layer address (MAC address) of an interface. For mapping of MAC addresses into Interface identifiers in IPv6 global unicast and other addresses, Extended Universal Identifier (EUI) is used. The 64-bit EUI format is derived from the 48-bit MAC address by inserting the hexadecimal number FFFE (16 bits) between the upper 3 bytes and the lower 3 bytes of the MAC address, and setting the 7th bit of the leftmost byte to 1.

This is new version.. It will take some years to implement.

 

hope this is use full to all.

 

How to Configure Static, Dynamic and Port NAT ?

 

You can follow the Following Steps:

Figure : Static and dynamic NAT Example

 

1. Static NAT Configuration :
To configure static inside source address translation for the example shown in above  Figure , the following need to be performed on the router:

• Specify the inside interface:
  • Router(config)#interface ethernet0
  • Router(config-if)# ip nat inside
• Specify the outside interface:
  • Router(config)#interface serial0
  • Router(config-if)# ip nat outside
• Enter static translation entry ¹:
  • Router(config)# ip nat inside source static 10.0.0.3 179.2.2.80

 

2. Dynamic NAT Configuration :

To configure dynamic inside source address translation for the example shown in above figure , the following need to be performed:

• Specify the inside interface:
  • Router(config)#interface ethernet0
  • Router(config-if)# ip nat inside
• Specify the outside interface:
  • Router(config)#interface serial0
  • Router(config-if)# ip nat outside
• Define an Access List to permit the inside local addresses to be translated ²:
  • Router(config)#access-list 1 permit 10.0.0.0 0.0.0.255
• Define a pool of global addresses ³:
  • Router(config)# ip nat pool figure1 179.2.2.65 179.2.2.90 netmask 255.255.255.224
• Enter dynamic translation entry ⁴:
  • Router(config)# ip nat inside source list 1 pool figure1

 

3.  Port NAT Configuration :

To configure NAT Overloading for the example shown in following figure , the following need to be performed on the router interfaces :

Figure PAT

• Specify the inside interface:
  • Router(config)#interface ethernet0
  • Router(config-if)# ip nat inside
• Specify the outside interface:
  • Router(config)#interface serial0
  • Router(config-if)# ip nat outside
• Define an Access List to permit the inside local addresses to be translated:
  • Router(config)#access-list 1 permit 10.0.0.0 0.0.0.255
• Enter dynamic translation entry ⁵:
  • Router(config)# ip nat inside source list 1 interface serial0 overload

 

Note : Some Important Commsnd syntaxs which useful during NAT configuration on Routers.

¹ Router(config)# ip nat inside source static [local IP address] [global IP address]
² Router(config)# access-list [access list number] permit
³ Router(config)# ip nat pool [pool name] [start IP address] [end IP address] netmask [netmask]
⁴ Router(config)# ip nat inside source list [access list number] pool [pool name]
⁵ Router(config)# ip nat inside source list [access list number] interface [interface] overload

 

I hope this is Helpful to all.

How to Translate Inside Local and Inside Global Address by NAT

 

1. Inside Local Source Address Translation :

 

Figure 1: NAT Example

Above The diagram  shows a router translating an inside source IP address to a source IP address for the outside network (1:1 Mapping).

Translation process follows these steps:

1. User at host 10.0.0.3 begins to send traffic to the router, destined for host at 212.31.80.2.
2. Upon receiving the first packet, the router checks its NAT table.
   1. If dynamic NAT is configured, the router picks up a free global address from its dynamic address pool (in the above example 179.2.2.80) and creates a translation entry into its NAT table.
   2. If static NAT is configured, the router automatically translates the inside local address: 10.0.0.3 with its equivalent global IP address: 179.2.2.80, and forwards the packet.
3. User at 212.31.80.2 replies to host 10.0.0.3 using the inside global destination address 179.2.2.80 (Destination address=179.2.2.80).
4. When the router receives the replied packet, it checks its NAT table again to find an entry for the inside global address 179.2.2.80. If a match is found, then the router translates the address back to its respective local address 10.0.0.3 and forwards it to the user.
5. The router continues to perform all the above steps for each packet it receives.

 

2. Inside Global Address Overloading :

 

Figure 2: NAT Overloading

 

From the above Figure, it can be seen that NAT overloading conserves register inside global IP addresses on the router. Inside local IP addresses are translated to a common global IP address and are distinguished between them by the use of different port numbers. Outside hosts do not see this translation; they believe they are talking to the same host with IP address 179.2.2.80, though they are actually talking to two different hosts.

 

Note : Read my Next Post How to configure SNAT, DNAT and PNAT. and Also read my previous Post “What is NAT”.