NAT-PT: Enabling Access Between IPv6 and IPv4

smart phoneNAT-PT stands for Network Address Translation Protocol Translation. This provides a translation protocol and an allocation address between network devices addressed as IPv6 and IPv4. During the session’s lifetime, the context and the state of each of the communications get retained. The process of translation is founded on the SIIT method or the State-less IP / ICMP Translations. UDP packets as well as TCP’s and ICMP’s are all supported by NAT-PT IPv6 which you can learn more about in this technology course.

It was mainly due to the coexistence of IPv6 and IPv4 networks that NAT-PT was introduced. For instance, this enables IPv4 network hosts to access an IPv4 network’s FTP server. This way, users of either network are able to communicate without changing a thing, as you can see in this article.

There is a vastly larger space for address with IPv6 compared to the exhausted, impending IPv4 address space. Using techniques such as Network Address Translation (NAT), this allows for private address ranges to be represented by a public single address and temporary assignment of addresses. There is technology for providing the transition mechanisms for the legacy host IPv4 to keep the internet connection which you can learn more about in this router administration course.

NAT-PT Operations

The devices J Series and the SRX series support the Traditional NAT-PT and allow static mapping for users to communicate from IPv6 and IPv4. Based on the DNS, users need to configure the DNS server statically with the IPv4 address for the host names and on the device begin creating static NAT for the nodes of IPv6-exclusive to communicate from the IPv4-exclusive nodes to the IPv6-only nodes.

The following types of NAT-PT are supported by the NAT-PT IPv6:

  1. Bi-directional NAT-PT

When it comes to NAT-PT that is categorized as ‘bi-directional,’ you can initiate sessions from IPv4 network hosts and the network IPv6. The network addresses of IPv6 are attached to addresses of IPv4, either dynamically or statistically as there are established connections in both directions. The static configurations are not unlike the NAT static translations. In the realm of IPv4, hosts access the realm of IPv6 hosts with the use of DNS for resolution of address. You need to employ DNSALG’s together with bi-directional NAT-PT in order for the mapping of name-to-address to be facilitated. In other words, addresses of IPv6 in responses and DNS queries that go to the address binding of IPv4 are addressed by IPv6, as the packets of DNS traverse between the realms of IPv4 and IPv6.

  1. Traditional

Traditional NAT-PT- this this version, there are outbound and unidirectional sessions from the network of IPv6. NAT-PT traditionally allows hosts within the network of IPv6 to access hosts in a network of IPv4. When it comes to traditional NAT-PT, there are 2 variations: NAPT-PT and basic NAT-PT.

NAPT-PT stands for Network Address Port Translations and Protocol Translations. This works in combination with the basic version so that an external address pool is utilized together with port translations. Sets of IPv6 hosts are allowed by the NAPT-PT to hare single IPv4 addresses. Related fields such as ICMP, UDP, TCP and IP headers checksums as well as source transport identifiers and the source IP address is translated by the NAT-PT for outbound packets from the network IPv6. The identifier transport can be an ICMP query ID or a TCP-UDP. For packets inbound, this translates the transport header checksums, the IP, the destination transport identifier and the destination IP address.

In basic NAT-PT, an IPv4 interface of an IPv4 block of addresses is set aside for address translations as IPv6 hosts as sessions are initiated to the hosts of IPv4. NAT-PT basic translates related fields like the ICMP header checksums, UDP, TCP, IP and the IP address for outbound packets from the domain of IPv6 as you can see in this course. For packets inbound, this translates the checksums and the IP address destination.

NAT-PT Prefix

The prefix format is addressed by the NAT-PT 96-bit and is used in cases such as these:

  • After an IPv4 host is translated through NAT-Pt into an IPv6 host, the translated source prefix IPv6 is configured in the prefix NAT-PT.
  • When a packet is received from the host of IPv6 to a host of IPv4, the device NAT-PT detects the destination prefix of the packet’s IPv6 address. If there is the same prefix as the configured NAT-PT prefix, the destination and source IPv6 addresses of this packet is translated into addresses of IPv4.

NAT-PT Works as Follows:

  1. The Reply Packet is Forwarded by NAT-PT According to the Stored Mapping

Once a reply is received from the host IPv4 to the IPv6 host, the device NAT-PT swaps the destination and source of the IPv4 address according to the mappings stored and forwards this packet to the host IPv6.

  1. Stores the Mapping and Forwards the Packet

After the destination and source IPv6 packet addresses are translated into the addresses of IPv4, the device NAT-PT forwards the packets to the host IPv4. In the meantime, the address mappings of IPv6/ IPv4 are stored in the device NAT-PT.

  1. The IP Address Destination is Translated

The device NAT-PT translates the IPv6 packet address into the address IPv4 according to the network side of IPv4. If the lowest thirty-two bits of the IPv6 destination in the packet can be translated directly to the valid address of IPv4, the IPv6 address destination is translated into the IPv4 address. If this does not occur, there will be a failed translation.

  1. Translates the IP address Source

The packet’s IPv6 address source is translated by the NAT-PT device into an IPv4 address according to the dynamic or static IPv6 mapping side.

  1. Determines whether NAT-PT will be Done or Not

Once and IPv6 host packet is received, the device NAT-PT detects the destination IPv6 packet address’ prefix. If there is the same prefix as the configured prefix of NAT-PT, the device considers that the packet should be forwarded to the network IPv4 and the NAT-PT, which you can learn more about in this IPV4 course.