what record in dns is used to specify that a host provides a specific type of service? quizlet

IPv6, the new version of the IP protocol, provides important new capabilities, including a larger address space, more flexible subnetting, simplified address assignment, and improved security.

As IPv6 adoption grows, DNS is becoming more of import as a mechanism to help users, using both IPv4 and IPv6 hosts, accomplish the most appropriate IP address.

If you operate your own DNS server, switching to IPv6 DNS requires configuration on your server, and creating two sets of records to ensure you tin continue to support traffic from IPv4 hosts.

Keep reading to acquire more almost:

• IPv6 basics and what are the differences between IPv4 and IPv6
• IPv6 adoption and the growing importance of DNS
• How IPv6 DNS works
• A quick guide to setting up IPv6 on your DNS server
• Avant-garde DNS services that leverage IPv6

What is IPv6?

Net Protocol Version 6 (IPv6) is a new version of the Internet Protocol (IP), the send machinery used for about advice on the Internet. Devices utilize numeric IP addresses to connect to each other within and between networks.

What is IPv6 used for? A master motivation for IPv6 is to offer more IP addresses. The previous version, IPv4, offered a limited address space, which is about exhausted.

In Internet Protocol Version 4 (IPv4), defined in RFC 791 in 1981, IP addresses are described using quad-dotted note, similar this:

192.168.1.1.

This notation provides an accost infinite of approx. 4.3 billion addresses. IPv6, defined in RFC 8200, uses 128-bit addresses with viii sets of iv hexadecimal characters. Hither'southward an example IPv6 accost:

ABCD:EF01:2345:6789:ABCD:EF01:2345:6789

The new notation increases the accost space to approx. 3.iv * 1038 addresses.

Differences Between IPv4 and IPv6

Beyond the different note, here are of import benefits of IPv6 compared to IPv4:

• Simplifies address assignment (stateless address automobile-configuration)
• Network renumbering
• Router announcements when irresolute network connectivity providers
• Simplified processing of packets in routers, moving package fragmentation to endpoints
• Improved network security, per the original specification of IPsec

IPv6 Subnetting

Another departure between IPv4 and IPv6 is in the definition of subnets. IPv4 addresses use the first 24 bits of the address as an optional subnet mask. In IPv6, addresses are divided into a 48 fleck routing prefix, a 16-bit subnet ID (together these ii define the subnet), and an Interface ID used for hosts only. Thus, IPv6 enables 65K more subnets than in IPv4.

Routing Prefix Subnet ID Interface ID

--------------------------|--------------------|-----------------------

48 bits 16 $.25 64 $.25

IPv4 and IPv6 Interoperability

The 2 protocols are not interoperable, so IPv4 hosts cannot communicate with IPv6 hosts at the protocol level. Yet, mechanisms have been developed to integrate older and newer hosts, and allow communication from IPv4 to IPv6 and vice versa. Two normally used mechanisms are DNS64 and NAT64.

IPv6 Adoption and the Growing Importance of DNS

IPv6 was introduced over a decade ago, and still, adoption is slow. At the time of this writing, simply 17.49% of devices on the Internet are currently IPv6 capable, while a larger proportion of DNS resolvers—over a third—are capable of handling IPv6 addresses. Either way, most of the Cyberspace is currently non IPv6 capable and therefore cannot leverage IPv6 DNS.

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Part of the reason for the delayed adoption of IPv6 is that over the years, mechanisms have emerged to serve more physical devices with the same limited IPv4 addresses:

• Classful networks—ameliorate distribution of IP addresses
• Classless inter-domain routing—flexible subnetting of internal networks
• Network Address Translation (NAT)—abstracts an entire network equally a single external-facing IP accost

Another reason is infrastructure—for the Net to fully switch over to IPv6, every router, switch and visible server must back up the standard. Currently about network hardware, and even new hardware beingness sold today, does non support IPv6. Even routers which theoretically support IPv6 practice not run it by default.

What is IPv6 DNS?

DNS helps users and network devices find other devices, by translating human-readable hostnames into IP addresses. A DNS Resolver is a software component, deployed every bit office of operating systems, routers and network services, which accepts a hostname similar "world wide web.example.com" and is responsible for finding the correct IP address for the hostname.

In IPv4, DNS was significant for Cyberspace usability considering people found it difficult to recall 12-digit IP addresses. With the transition to IPv6, DNS becomes critical, considering it'due south even less likely that y'all'll call back a 128-bit hexadecimal address.

As the Net shifts from IPv4 to IPv6, hostnames stay the same. A user will continue requesting the same website, unaware that behind the scenes that site may or may not have transitioned to a 128-bit IPv6 accost.

As the Net transitions from IPv4 to IPv6, organizations and infrastructure providers volition increasingly rely on DNS, equally a mediator that can help span the gap between IPv4 and IPv6.

Quick Guide: DNS IPv6 Setup

Important note: The instructions below apply if y'all are setting up an on-premise DNS server. If you opt to use a hosted DNS service, there'south no demand to set anything up. Just make sure your DNS provider supports IPv6.

Follow these steps to make your DNS server attainable over IPv6:

1. Setup IPv6 on your DNS server—here is a tutorial which shows how to practise this in Demark installed on Debian.

1. Add together IPv6 addresses as a DNS record for your hostname, so it has both A (IPv4 accost mapping) and AAAA (IPv6 address mapping) records. Here is an example of an AAAA record:

case-host IN AAAA 2830:0:1edf:j1ok:b25c::5

1. Ensure you also correctly setup PTR (reverse DNS) records for your IPv6 addresses. IPv6 PTR records take the IP accost written in contrary nibble format, just like in IPv4, simply the accost is much longer. Note that the trailing domain in-addr.arpa has inverse to ip6.arpa.

Reverse DNS v6 is a free tool that can help y'all create AAAA file entries in BIND, as well as the respective A and PTR records.

1. Inform the domain registrar nigh the new accost. In order for DNS to consul correctly, the DNS zone one step higher in the hierarchy needs to have a "glue tape" pointing to your name server. For example, if your hostname is example-host.com, the .com zone needs to maintain a glue record for all your name servers. Today most all Top Level Domains (TLD) support IPv6.

1. Ensure you lot provide identical data for the same hostname over IPv6 records every bit you practise over IPv4. Many clients will not have IPv6 back up. In add-on, while a client may originally perform a DNS query using IPv6, name servers in the DNS resolution chain might be dual stack and might forward the request over IPv4, or an IPv4 address could be locally cached.

1. DNS SRV records betoken how your DNS server prefers that clients connect. If, for example, you lot would similar to prioritize IPv6 because you take a fast IPv6 tunnel, y'all can ready an SRV tape such every bit:

   example.com. IN AAAA 2830:0:1edf:j1ok:b25c::5
   slow-tunnel.example.com. IN A 192.168.2.100

   _sip._tcp.instance.com. 86400 IN SRV 10 5 5060 case.com.
   _sip._tcp.case.com. 86400 IN SRV twenty five 5060 slow-tunnel.example.com.

   This specifies that an IPv4 client should connect first to tiresome-tunnel.example.com. An IPv6 customer volition run into that the lowest priority server is IPv4, and switch to the 2nd priority, example.com. A dual stack client will exercise the same and connect to example.com.

You tin can also employ the Happy Eyeballs protocol to dynamically serve either IPv4 or IPv6 depending on which will give the user the optimal experience.

Which DNS Server to Use for IPv6?

According to this comprehensive comparison from Wikipedia, well-nigh all popular DNS servers support IPv6, including the world'southward most popular server, BIND (starting from version four.x). When deploying an on-premise DNS server, ensure you are using a version that supports IPv6.

IPv6 with Advanced DNS Routing

While IPv6 is a large step forrad, DNS systems leveraging IPv6 have the aforementioned capabilities. As you movement to the next generation of IP, consider in tandem using the next generation of DNS engineering.

Modern DNS providers like NS1 operate IPv6 DNS servers with vastly improved performance, light-speed propagation and advanced traffic management features. Bank check if your provider of selection supports IPv6.

NS1's DNS platform fully supports IPv6 and provides the following advanced features:

• Instant propagation—NS1 operates a global network that can propagate DNS changes in milliseconds.
• Location aware—NS1 learns the geolocation of each DNS resources, determines user location via geo-IP, routes user requests dynamically by proximity.
• Load, capacity and toll aware—NS1 obtains traffic parameters for each resources, such equally capacity, load, and concurrent connections, and makes an optimal routing conclusion.
• Bandwidth and connectivity aware—NS1 performs health checks on resource to check their availability, bandwidth and network latency, and routes users to the best resource currently bachelor.

Get a gratuitous trial of NS1's adjacent generation IPv6 DNS platform.

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Source: https://ns1.com/resources/ipv6-dns-understanding-ipv6-and-a-quick-implementation-guide

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