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IPv6 Support in Exchange 2007 SP1 and SP2

Microsoft Exchange Server 2007 will reach end of support on April 11, 2017. To stay supported, you will need to upgrade. For more information, see Resources to help you upgrade your Office 2007 servers and clients.

 

Applies to: Exchange Server 2007 SP1, Exchange Server 2007 SP2

This topic explains the support for Internet Protocol Version 6 (IPv6) addressing in Microsoft Exchange Server 2007 Service Pack 1 (SP1) and Exchange 2007 Service Pack 2 (SP2).

What is IPv6?

IPv6 is a new version of the Internet Protocol. The current version of the Internet Protocol is known as Internet Protocol Version 4 (IPv4). IPv6 is intended to correct many of the shortcomings of IPv4, such as a decreasing pool of available addresses, lack of extensibility, and lack of autoconfiguration. For example, IPv6 addresses are 128-bits long. In contrast, IPv4 addresses are 32-bits long. There are enough IPv6 addresses for every person on earth to have trillions and trillions of IPv6 addresses assigned to them.

Because IPv4 and IPv6 are completely different protocols, an IPv4 network can't communicate directly with an IPv6 network, and vice versa. Network administrators deploy devices, such as routers, that can route information between IPv4 networks and IPv6.

Although IPv6 was officially defined in RFC 2460 in 1996, native IPv6 environments are rare. Most administrators deploy a dual environment where both IPv4 and IPv6 are configured and supported on the network.

For more information about IPv6, see IPv6.

Windows Support for IPv6

IPv6 is supported in the following Microsoft server operating systems:

  • Windows Server 2008  By default, the IPv6 protocol and the IPv4 protocol are both installed and enabled. When both IPv4 and IPv6 are enabled, IPv6 is given preference over IPv4. Additionally, you can remove the IPv4 protocol so that the server runs IPv6 exclusively.

  • Windows Server 2003   By default, the IPv6 protocol isn't installed. However, it can be added. You can't uninstall the IPv4 protocol if the IPv6 protocol is installed.

IPv6 is supported in the following Microsoft desktop operating systems:

  • Windows Vista   By default, the IPv6 protocol and the IPv4 protocol are both installed and enabled. When both IPv4 and IPv6 are enabled, IPv6 is given preference over IPv4. Additionally, you can remove the IPv4 protocol so that the computer runs IPv6 exclusively.

  • Windows XP Service Pack 1 (SP1) or later   By default, the IPv6 protocol isn't installed. However, it can be added. You can't uninstall the IPv4 protocol if the IPv6 protocol is installed.

Exchange 2007 Support for IPv6

IPv6 is only supported in Exchange 2007 SP1 and SP2 when it is installed on a Windows Server 2008 computer that has both IPv4 and IPv6 enabled. If you disable the IPv4 protocol, Exchange 2007 can't support IPv6.

Note

You may be able to enter IPv6 addresses in the Exchange Management Console or the Exchange Management Shell in the release to manufacturing (RTM) version of Exchange 2007 on a server that runs Microsoft Windows Server 2003, and in Exchange 2007 SP1 and SP2 on a Windows Server 2003. However, IPv6 is not supported in any version of Exchange 2007 on a server that is running Windows Server 2003.

Also, remember also that Exchange management tasks can be run remotely so that you can configure any Exchange server in your organization from the management interfaces of any other Exchange server or from a workstation that has the administrative tools installed. The IP addressing capabilities are limited by the target of the operation, not by the computer on which the task is run.

Basic Information About IPv6 Addresses

An IPv6 address is 128-bits long. The address is described by using colon-hexadecimal notation. Colon-hexadecimal notation describes the 128-bit address by using eight 16-bit, 4-digit hexadecimal numbers that are separated by the colon character ( : ). An example of an IPv6 address in colon-hexadecimal notation is 2001:0DB8:0000:0000:02AA:00FF:C0A8:640A.

You can express an IPv6 address by using the following methods:

  • Suppress leading zeros   You can omit the leading zeros in any of the eight 4-digit hexadecimal numbers in an IPv6 address.

  • Double-colon compression   You can use two colons ( :: ) to represent contiguous 16-bit hexadecimal digits that contain all zeros. These all-zero digits may exist at the beginning, middle, or end of the IPv6 address. You can only use double-colon compression one time in an IPv6 address.

  • Trailing dotted decimal notation   You may express the last 32 bits at the end of an IPv6 address in dotted-decimal notation by separating the 8-bit digits with a period ( . ). Trailing dotted-decimal notation is frequently used with IPv4-compatible addresses.

The following table provides a comparison of the equivalent IPv6 address syntax is described.

A comparison of the equivalent IPv6 address syntax

IPv6 address notation IPv6 address

Full IPv6 address

2001:0DB8:0000:0000:02AA:00FF:C0A8:640A

IPv6 address that uses suppressed leading zeros

2001:DB8:0:0:2AA:FF:C0A8:640A

IPv6 address that uses double-colon compression

2001:DB8::2AA:FF:C0A8:640A

IPv6 address that uses trailing dotted-decimal notation

2001:DB8::2AA:FF:192.168.100.10

IPv6 addresses may be categorized into the following types:

  • Unicast address   A packet is delivered to one interface.

  • Multicast address   A packet is delivered to multiple interfaces.

  • Anycast address   A packet is delivered to the nearest of multiple interfaces. The distance between interfaces is defined by the routing cost.

IPv6 unicast addresses have the following possible scopes:

  • Link-local   The scope of the IPv6 address is the local subnet. IPv6 link local addresses are comparable to IPv4 link local addresses that are used in Automatic Private IP Addressing (APIPA).

  • Site-local   The scope of the IPv6 address is the local organization. Site local addresses were deprecated by RFC 3879 and replaced by unique local addresses as defined in RFC 4193. IPv6 site local addresses and IPv6 unique local addresses are comparable to IPv4 private IP addresses.

  • Global   The scope is of the IPv6 address is the whole world. IPv6 global addresses are comparable to IPv4 public IP addresses.

The following table provides a comparison of IPv4 elements and IPv6 elements.

A comparison of IPv4 elements and IPv6 elements

Item IPv4 IPv6

Private IP addresses

10.0.0.0/8

172.16.0.0/12

192.168.0.0/16

FD00::/8

Link local addresses

169.254.0.0/16

FE80::/64

Loopback address

127.0.0.1

::1

Unspecified address

0.0.0.0

::

Address resolution

Address Resolution Protocol (ARP)

Neighbor Discovery (ND)

DNS host name resolution

"A" record

"AAAA" record or "A6" record

For more information about IPv6 addressing, see IPv6 Address Types.

Supported IPv6 Input Formats in Exchange 2007 SP1 and SP2 on Windows Server 2008

You may have to enter an IPv6 address in the following situations:

  • A single IPv6 address

  • An IPv6 address range

  • An IPv6 address together with a subnet mask

  • An IPv6 address together with a subnet mask that uses Classless Inter-Domain Routing (CIDR) notation

In Exchange 2007 SP1 and SP2 on Windows Server 2008, the suppression of leading zeros, double-colon compression, and trailing dotted decimal notation are supported.

The acceptable IPv6 address input formats in Exchange 2007 SP1 and SP2 on Windows Server 2008 are described in the following table.

Acceptable IPv6 address input formats in Exchange 2007 SP1 and SP2 on Windows Server 2008

Type IPv6 address example

Single address

2001:DB8::2AA:FF:C0A8:640A

Address together with subnet mask

2001:DB8::2AA:FF:C0A8:640A(FFFF:FFFF:FFFF:FFFF::)

Address together with subnet mask that uses CIDR notation

2001:DB8::2AA:FF:C0A8:640A/64

Address range

2001:DB8::2AA:FF:C0A8:640A-2001:DB8::2AA:FF:C0A8:6414

IPv6 Support in Exchange 2007 SP1 and SP2 Components

The following table describes the components in Exchange 2007 SP1 and SP2 that are directly affected by IPv6. If a component is not mentioned, you can assume that it is unaffected by IPv6 addressing and functions correctly.

Exchange 2007 SP1 and SP2 components that are directly affected by IPv6

Source Feature IPv6 supported? Comments

Transport

IP Allow List and IP Block List

Yes

For more information about the IP Allow list, see How to Add IP Addresses to the IP Allow List and IP Block List.

Transport

IP Allow List providers and IP Block List providers

No

Currently, there is no widely accepted industry standard protocol for looking up IPv6 addresses. Most IP Block List providers do not support IPv6 addresses. Therefore, if you allow anonymous connections from unknown IPv6 addresses on a Receive connector, you increase the risk that spammers will bypass IP Block List providers and successfully deliver spam into your organization.

For more information about the IP Block list providers, see How to Configure IP Allow List and IP Block List Providers.

Transport

Sender reputation

No

The Protocol Analysis agent does not compute the sender reputation level (SRL) for messages that originate from IPv6 senders. For more information about sender reputation, see Sender Reputation.

Transport

Sender ID

Yes

For more information, see Sender ID.

Transport

Receive connectors

Yes

IPv6 addresses are accepted for the following components:

  • Local IP address bindings

  • Remote IP addresses and IP address ranges

We strongly recommend against configuring Receive connectors to accept anonymous connections from unknown IPv6 addresses. If your organization must receive mail from senders who use IPv6 addresses, create a dedicated Receive connector that restricts the remote IP addresses to the specific IPv6 addresses that those senders use.

For more information, see Receive Connectors.

Transport

Send connectors

Yes

IPv6 addresses are accepted for the following components:

  • Smart host IP addresses

  • The SourceIPAddress parameter for Send connectors that are configured on Edge Transport servers

    Note

    If you want to specify an IPv6 address for the SourceIPAddress parameter, make sure that the appropriate DNS AAAA and MX records are configured correctly. This helps ensure message delivery if a remote messaging server tries any kind of reverse look-up test on the specified IPv6 address.

For more information, see Send Connectors.

Transport

Incoming message rate limits

Partial

Incoming message rate limits that you can set on a Receive connector, such as MaxInboundConnectionPercentagePerSource parameter, the MaxInboundConnectionPerSource parameter, and the TarpitInterval parameter only apply to global IPv6 address. Link local IPv6 addresses and site local IPv6 addresses are not affected by any specified incoming message rate limits. For more information about incoming message rate limits, see Managing Message Throttling.

Unified Messaging

All features

No

Unified Messaging doesn't support IPv6 in any version of Exchange 2007. For more information, see Unified Messaging.

High Availability

IPv6 addresses

Yes

Static IPv6 addresses are supported by Windows Server 2008 and the Microsoft Windows Cluster service. However, using static IPv6 addresses goes against best practices. Therefore, Exchange 2007 SP1 and SP2 on Windows Server 2008 doesn't support configuring static IPv6 addresses during setup.

Failover clusters support Intrasite Automatic Tunneling Addressing Protocol (ISATAP). They support only IPv6 addresses that allow for dynamic registration in DNS. Therefore, link local addresses can't be used in a cluster.

For more information, see New High Availability Features in Exchange 2007 SP1.

Outlook Anywhere

DSProxy component

No

When a client that is using Outlook Anywhere tries to connect to Exchange 2007 SP1 and SP2 running on Windows Server 2008, the client cannot connect. This happens because the RPCProxy component on the Client Access server that is running under Windows Server 2008 cannot connect through port 6004 to the DSProxy component on the Exchange Mailbox server.

For more information, see White Paper: Outlook Anywhere Scalability with Outlook 2007, Outlook 2003, and Exchange 2007

Disable or Enable IPv6

Exchange servers fully support IPv6 networks, and there is no need to disable IPv6 on your Exchange servers. To learn more about IPv6 support for Microsoft Windows, see IPv6 for Microsoft Windows: Frequently Asked Questions.