Top 28 Internet Protocol Version 6 (IPV6) Interview Questions You Must Prepare 29.Nov.2023


If a host configures its ip address by contacting DHCP, it is called as STATEFUL ADDRESS CONFIGURATION.

If a host configures its ip address without DHCP, it is STATELESS ADDRESS CONFIGURATION. Normally the address is derived from the prefixes advertised by Local Routers.

Even in the absense of Routers also, hosts can automatically configure themselves (called link-local address).

The imminent need to migrate systems to the IPv6 protocol does not exist the way we saw with Y2K. As a result, enterprises have frequently decided to postpone investment in the trition. One of the reasons is that IPv6 deployment is a necessary upgrade procedure that requires the investment of human and capital resources, but does not offer clear short-term return. There are also workarounds, such as the introduction of Network Address Trlation (NAT) that allows organisations to extend their addresses to more devices.  These workarounds are costly and not viable in the long-term. The only way forward is to adopt IPv@The time to adopt is now - and many organizations have already initiated, and even completed the trition process.

On 4 February 2008, ICANN announced that it had added IPv6 to six of the 13 root servers, namely A, F, H, J, K, M, thus allowing for a fuller IPv6 usage of the Domain Name System (DNS). Since then, the L root has also been added to the list.

The lenth of IPV6 ip address is 128 bits.

Since network needs and businesses differ, IPv6 trition strategies and related costs will also vary between organisations. Hardware and software vendors are increasingly integrating IPv6 as a standard feature in products, allowing organisations to deploy IPv6 as part of routine upgrade cycles. For many organisations, operational costs, including staff training, and one-time administrative costs to add IPv6 to management databases and documentation, are likely to constitute the majority of the cost of upgrading to IPv@Organisations that run in-house customised software will experience additional costs to upgrade these programs to IPv6, and enterprises that have test/release processes will see a marginal additional cost for the IPv6 configuration tests.

For end-users, operating systems such as Mac OS X, Windows, and Linux now incorporate IPv6 within their latest releases and will automatically use IPv6 if it is available. Applications are expected to follow as the global demand for IPv6 increases.

  • IPV6 is of fixed 40byte header.
  • IPV4 it is variable(normally 20 bytes).

  • ethertype of ipv4  is 08@
  • ethertype of ipv6  is 86DD.

No. Both IPv4 and IPv6 will run in parallel until there is no longer any need to do so.

The main advantage of IPv6 is that it provides much more address space. Being a more recent protocol, IPv6 does have a few design improvements over IPv4, particularly in the areas of autoconfiguration, mobility, and extensibility. However, increased address space is the main benefit of IPv6.

Simply by having a lot more address space to uniquely identify devices that are connected to the Internet. IPv4 has a theoretical maximum of about 4 billion addresses whereas IPv6 has an unthinkable theoretical maximum: about 340 trillion, trillion, trillion addresses. In actual use, IPv6 addresses are structured for routing and other purposes and as a result the number of addresses available is effectively less, but still extremely large.

For the end user, the large amount of IPv6 address space me:

Home users will generally be given blocks of addresses sufficient to number multiple networks and thousands of devices. (In contrast, under IPv4, home users today typically get a single address.)

Enterprises and small businesses will generally be given enough to number a substantial number of networks and tens of thousands of devices; while larger sites will get significantly more.

Trlating addresses does not provide any security benefits. In many cases NATs require an outgoing connection to be present before they will allow an incoming connection to succeed. This 'stateful packet filtering' can be enabled for IPv6 in the absence of any address trlation. The security properties of IPv6 are no different than those of IPv4.

Our goal with IPv6 Day is to ensure that the Internet continues to operate smoothly, allowing users to continue to access Web content and services quickly and easily. However, as IPv6 Day will be the first time the next-generation Internet protocol is used at a global scale, we anticipate there will be some hiccups.

The impact will vary depending on the exact hardware, Internet service and Web services an individual is trying to use. In some rare cases, users may have broken IPv6 connectivity and thus may not be able to access services on IPv6 Day. This is often due to misconfigured or misbehaving equipment (e.g., home routers) or software (e.g., firewalls). This problem currently impacts approximately one Internet user in every 2,0@Operating system vendors, home router vendors, and ISPs are working together to substantially reduce the number of affected users before World IPv6 Day.

Payload Length field is 16 bits.But if the payload size is more than 64k, then there is a problem in writing the value of payload length in this field. Under such circustances, ZERO will be written in the payload length field and the details of payload length will be written in HOP BY HOP OPTIONS EXTENSION HEADER.

By the way, if the payload size is greater than 64k, it is called as JUMBOGRAM.

IPv6 is the new version of the Internet address protocol that has been developed to supplement (and eventually replace) IPv4, the version that underpins the Internet today.

No. An enormous amount of IP address space exists under IPv@IPv6, in fact, was specifically designed to fix the address limitations of IPv@This addressing capacity will enable the trillions of new Internet addresses needed to support connectivity for a huge range of smart devices such as phones, household appliances and vehicles.

An anycast address is a single address assigned to multiple nodes. 

A packet sent to an anycast address is then delivered to the first available node.  It is for  load-balancing and automatic failover.

Several of the DNS root servers use a router-based anycast implementation, which is really a shared unicast addressing scheme. (While there are only thirteen authoritative root server names, the total number of actual servers is considerably larger, and they are spread all over the globe.) The same IP address is assigned to multiple interfaces, and then multiple routing tables entries are needed to move everything along.

IPv6 anycast addresses contain fields that identify them as anycast, so all you need to do is configure your network interfaces appropriately. The IPv6 protocol itself takes care of getting the packets to their final destinations.

  • Version(4)
  • Traffic Class(8)
  • Flow Label(20)
  • Payload Length(16)
  • Next Header(8)
  • Hop Limit(8)
  • Source Address(128)
  • Destination Address(128)

The trition to IPv6 will require collaboration across the Internet industry:

Internet service providers, Web companies, hardware vendors and operating system vendors. All major industry players need to take action to ensure products and services are ready for the trition. For example, Internet service providers need to make IPv6 connectivity available to their users, Web companies need to offer their sites and applications over IPv6, operating system vendors may need to implement specific software updates, backbone providers may need to establish IPv6 peering with each other, and hardware and home gateway gateway manufacturers may need to update firmware.

IPv6 is an important part of ensuring continued growth and accessibility of your services to the rest of the Internet and emerging markets in particular. As the Internet progressively becomes a dual IPv4/IPv6 network, ensuring that you are IPv6 enabled will be critical for retaining universal Internet connectivity for your clients, users, and subscribers, business partners and suppliers. Indeed, as the difficulty and cost of obtaining IPv4 address space increases, it is inevitable that some sites will only support IPv@Connectivity with such sites (and customers) will require IPv6.

It is also worth considering what services and devices may need to be supported over the next few years as the remaining IPv4 pool become depleted. Your existing address allocations may be insufficient to support a sudden increase in the number of connected devices per person (as many organisations experienced with the rapid deployment of IP-enabled wireless handheld products and similar devices a few years ago).

The Internet Engineering Task Force (IETF), an international group concerned with developing technical standards that make the Internet work better first published the basic IPv6 protocol in 199@It has since seen a number of enhancements, such as the addition of mobile IPv6 specifications (in 2004).

  1. TCP (6)
  2. UDP(17)
  3. No Next Header(59)
  4. Routing Header(43)
  5. Fragment Header(44)
  6. Hop by Hop Options Header(0)
  7. Resource ReSerVation Protocol(46)
  8. Encapsulating Security Payload(50)
  9. Authenticaion Header(51)
  10. ICMPv6(58)
  11. Destination Options Header(60)
  12. Encapsulated IPv6 Header(41)

The big difference is that sharing is now across multiple subscribers, as opposed to across multiple devices belonging to a single subscriber. This has implications for advertisers, content providers, law enforcement and end-users themselves. NAT in residential cable modems and the like is often configurable by the subscriber. Service-provider NAT will offer less possibility for end-user configuration. This me the subscriber's ability to enable incoming connections for applications like VoIP or gaming may be curtailed.

FF02::1:FF00:0/104 is the prefix and 24 bits of ipv6 is appended at the end.Hence FF02::1:FF28:9C5A is the solicted node address

No one will put a date on when IPv4 will be turned off. This will depend on market forces. When IPv6 becomes the dominant network it will draw more people in and less people will worry about IPv@There will always be backwards compatibility for things like older network printers that cannot trition to IPv6.

You will need to obtain new IPv6 addresses in addition to your existing IPv4 address blocks. IPv4 address space that you have today can still be used in a dual IPv4-IPv6 environment. The RIRs all have policies that make it straightforward for an ISP with IPv4 space to apply for and receive IPv6 address space. You should contact the RIR for your region or your ISP for more information on how to acquire IPv6 addresses.

It may also be good idea to use this opportunity to redesign your addressing plan, taking advantage of the greater flexibility of IPv6 to assign subscriber address blocks more optimally. Similarly, customer sites may use IPv6 as an opportunity to redesign and optimise their internal addressing plan. However, it may be possible to re-use an existing subnet addressing plan within the new IPv6 block, if that is preferred.

No. There is no specific date when everything must be upgraded to IPv6 (although some organisations, including governments, have already identified target dates for their own IPv6 implementation. IPv6 and its trition mechanisms have been designed for a long period of co-existence with IPv4 and it is expected that IPv4-only systems and applications will survive for many years. However, IPv6-only systems are expected to arise and many of these users are likely to be in emerging business markets and developing countries.

Implementing IPv6 requires planning and with IPv4 address pool exhaustion expected around 2010-2011, planning needs to start now. Network operators and administrators should already be incorporating IPv6 into their network upgrade and procurement pl.