Showing posts with label DNS. Show all posts
Showing posts with label DNS. Show all posts

Tuesday, February 1, 2011

IPv6 Basics II - Differences Between IPv4 and IPv6


IPv4
IPv6
Source and destination addresses are 32 bits (4 bytes) in length.
Source and destination addresses are 128 bits (16 bytes) in length. For more information, see “IPv6 Addressing.”
IPsec support is optional.
IPsec support is required. For more information, see “IPv6 Header.”
No identification of packet flow for QoS handling by routers is present within the IPv4 header.
Packet flow identification for QoS handling by routers is included in the IPv6 header using the Flow Label field. For more information, see “IPv6 Header.”
Fragmentation is done by both routers and the sending host.
Fragmentation is not done by routers, only by the sending host. For more information, see “IPv6 Header.”
Header includes a checksum.
Header does not include a checksum. For more information, see “IPv6 Header.”
Header includes options.
All optional data is moved to IPv6 extension headers. For more information, see “IPv6 Header.”
Address Resolution Protocol (ARP) uses broadcast ARP Request frames to resolve an IPv4 address to a link layer address.
ARP Request frames are replaced with multicast Neighbor Solicitation messages. For more information, see “Neighbor Discovery.”
Internet Group Management Protocol (IGMP) is used to manage local subnet group membership.
IGMP is replaced with Multicast Listener Discovery (MLD) messages. For more information, see “Multicast Listener Discovery.”
ICMP Router Discovery is used to determine the IPv4 address of the best default gateway and is optional.
ICMP Router Discovery is replaced with ICMPv6 Router Solicitation and Router Advertisement messages and is required. For more information, see “Neighbor Discovery.”
Broadcast addresses are used to send traffic to all nodes on a subnet.
There are no IPv6 broadcast addresses. Instead, a link-local scope all-nodes multicast address is used. For more information, see “Multicast IPv6 Addresses.”
Must be configured either manually or through DHCP.
Does not require manual configuration or DHCP. For more information, see “Address Autoconfiguration.”
Uses host address (A) resource records in the Domain Name System (DNS) to map host names to IPv4 addresses.
Uses host address (AAAA) resource records in the Domain Name System (DNS) to map host names to IPv6 addresses. For more information, see “IPv6 and DNS.”
Uses pointer (PTR) resource records in the IN-ADDR.ARPA DNS domain to map IPv4 addresses to host names.
Uses pointer (PTR) resource records in the IP6.ARPA DNS domain to map IPv6 addresses to host names. For more information, see “IPv6 and DNS.”
Must support a 576-byte packet size (possibly fragmented).
Must support a 1280-byte packet size (without fragmentation). For more information, see “IPv6 MTU.”

IPv6 Basics I - Features of IPv6


IPv6 Features

The following are the features of the IPv6 protocol:
·         New header format
·         Large address space
·         Efficient and hierarchical addressing and routing infrastructure
·         Stateless and stateful address configuration
·         Built-in security
·         Better support for prioritized delivery
·         New protocol for neighboring node interaction
·         Extensibility
The following sections discuss each of these new features in detail.

New Header Format

The IPv6 header has a new format that is designed to keep header overhead to a minimum. This is achieved by moving both non-essential fields and optional fields to extension headers that are placed after the IPv6 header. The streamlined IPv6 header is more efficiently processed at intermediate routers.
IPv4 headers and IPv6 headers are not interoperable. IPv6 is not a superset of functionality that is backward compatible with IPv4. A host or router must use an implementation of both IPv4 and IPv6 in order to recognize and process both header formats. The new IPv6 header is only twice as large as the IPv4 header, even though IPv6 addresses are four times as large as IPv4 addresses.

Large Address Space

IPv6 has 128-bit (16-byte) source and destination IP addresses. Although 128 bits can express over 3.4´1038 possible combinations, the large address space of IPv6 has been designed to allow for multiple levels of subnetting and address allocation from the Internet backbone to the individual subnets within an organization.
Even though only a small number of the possible addresses are currently allocated for use by hosts, there are plenty of addresses available for future use. With a much larger number of available addresses, address-conservation techniques, such as the deployment of NATs, are no longer necessary.

Efficient and Hierarchical Addressing and Routing Infrastructure

IPv6 global addresses used on the IPv6 portion of the Internet are designed to create an efficient, hierarchical, and summarizable routing infrastructure that is based on the common occurrence of multiple levels of Internet service providers. 

Stateless and Stateful Address Configuration

To simplify host configuration, IPv6 supports both stateful address configuration, such as address configuration in the presence of a DHCP server, and stateless address configuration (address configuration in the absence of a DHCP server). With stateless address configuration, hosts on a link automatically configure themselves with IPv6 addresses for the link (called link-local addresses) and with addresses derived from prefixes advertised by local routers. Even in the absence of a router, hosts on the same link can automatically configure themselves with link-local addresses and communicate without manual configuration.

Built-in Security

Support for IPsec is an IPv6 protocol suite requirement. This requirement provides a standards-based solution for network security needs and promotes interoperability between different IPv6 implementations.

Better Support for Prioritized Delivery

New fields in the IPv6 header define how traffic is handled and identified. Traffic identification using a Flow Label field in the IPv6 header allows routers to identify and provide special handling for packets belonging to a flow, a series of packets between a source and destination. Because the traffic is identified in the IPv6 header, support for prioritized delivery can be achieved even when the packet payload is encrypted with IPsec.

New Protocol for Neighboring Node Interaction

The Neighbor Discovery protocol for IPv6 is a series of Internet Control Message Protocol for IPv6 (ICMPv6) messages that manage the interaction of neighboring nodes (nodes on the same link). Neighbor Discovery replaces the broadcast-based Address Resolution Protocol (ARP), ICMPv4 Router Discovery, and ICMPv4 Redirect messages with efficient multicast and unicast Neighbor Discovery messages.

Extensibility

IPv6 can easily be extended for new features by adding extension headers after the IPv6 header. Unlike options in the IPv4 header, which can only support 40 bytes of options, the size of IPv6 extension headers is only constrained by the size of the IPv6 packet.



Friday, December 31, 2010

DNS Infrastructures Lab


DNS Infrastructures Lab | 1.2GB


Video 1
Concepts Video
When you are getting started with DNS you need to know the basic concepts in order to move forward with more detailed information. This video will provide you with a good base of knowledge so that you can benefit from the rest of the course.
* DNS Namespace
* Name Resolution
* Root Hints
* SRV Records
* Authoritative

Video 2
DNS Installation
Installing DNS can be easy if you follow along with the Configure Your Server wizard, but you are not getting the full understanding of how to install DNS properly. You will benefit from this video because you will see an alternate manual way to install DNS that will allow you to configure it and troubleshoot it to best suit your needs.
* DNS Installation Options
* DNS Suffices
* Forward Lookup Zone Creation
* Reverse Lookup Zone Creation
* Host and PTR Records
* DNS Client Configuration
* NSLookup Commands

Video 3
Secondary DNS Configuration
You will benefit from this video by being able to do zone transfers, setting up secondary forward and reverse lookup zones, and DNS recovery. This video will also benefit you because you will see how to configure these settings on a second server.
* DDNS on Server 2
* Install DNS on Server 2
* Setup a Secondary Forward Lookup Zone
* Setup a Secondary Reverse Lookup Zone
* Zone Transfer Settings
* Other Zone Settings
* DNS Client Configuration
* DNS Recovery

Video 4
DNS Settings and Options
The benefit of this video is that you will be able to see some new settings that were not available in previous versions of Windows Server and you will be able to view changes to settings and other options that will allow you to tailor DNS to your needs.
* Lab Setup
* Active Directory Installation
* Child Domain
* DNS Domain
* DNS Delegation
* DNS Replication Settings
* Stub Zones
* DNS Forwarders
* Conditional Forwarding
* Caching-only DNS

Video 5
Configuring Public and Private DNS
The major benefit of this video is that you will get to take a look at a complete environment, which will show you how you can set up your own network internally and externally.
* Diagram/Explanation of Goals
* Test and Configure Internal DNS
* Configure Forwarding
* Public DNS Overview
* DNS Zone Configuration (public)
* Zone Transfers
* Host Records/Alias Records
* Testing from the client



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