You have two servers named Server1 and Server2 thatrun Windows Server 2012. Server1 has the DHCP
Server server role installed.
You need to create an IPv6 reservation for Server2.
Which two values should you obtain from Server2? (Each correct answer presents part of the solution. Choose
two.)
A.
the hardware ID
B.
the DHCPv6 unique identifier
C.
the DHCPv6 identity association ID
D.
the SMSBIOS GUID
E.
the MAC address
Explanation:
The Add-DhcpServerv6Reservation cmdletreserves a specified IPv6 address for the client
identified by the specified Dynamic Host Configuration Protocol (DHCP) v6 unique identifier (ID) (DUID) and
identity association ID (IAID).
C-D
To create an IPv6 address reservation in IPAM, you must first ensure that a valid IP address and MAC address are entered under Basic Configurations. Choose a Managed by service value of MS DHCP and a Service instance value corresponding to a valid managed DHCP server (ex: dhcp1.contoso.com). When these fields have been configured, click DHCP Reservation and choose a value for Reservation server name from the drop-down list. Reservation scope name and Reservation scope detail fields will be automatically populated. Enter required values for DUID, IAID, and Reservation name. Reservation description is optional. Click OK to enter the DHCP reservation into the IPAM database, or click Apply to commit the current values and continue entering more information.
0
0
B-C
0
0
You are right.
It is B and C.
Explanation:
The Add-DhcpServerv6Reservation cmdlet reserves a specified IPv6 address for the client identified by the specified Dynamic Host Configuration Protocol (DHCP) v6 unique identifier (ID) (DUID) and identity association ID (IAID).
Add-DhcpServerv6Reservation
Applies To: Windows 8.1, Windows PowerShell 4.0, Windows Server 2012 R2
Adds an IPv6 Reservation to an IPv6 prefix or scope.
The Add-DhcpServerv6Reservation cmdlet reserves a specified IPv6 address for the client identified by the specified Dynamic Host Configuration Protocol (DHCP) v6 unique identifier (ID) (DUID) and identity association ID (IAID).
EXAMPLE 1
This example reserves the specified IPv6 address for the specified ClientDuid and Iaid parameter values. After the reservation is added, the DHCP server service will assign only the specified IP address to the client request which contains the specified ClientDuid and Iaid parameter values.
PS C:\> Add-DhcpServerv6Reservation -Prefix 2001:4898:7020:1020:: -IPAddress 2001:4898:7020:1020::1 -ClientDuid 00-01-00-01-15-F9-7F-AB-F0-DE-F1-7A-00-5E -Iaid 234890455
—————————————————————————————-
Where can we find the DUID and the IAID?
We sneaked out of the lab to take a look at the Microsoft Windows DHCP server support for IPv6 and discussed how to assign an address to a specific computer, not just taking an address from a pool. The DHCP server need the DUID and IAID to be able to do this.
The question is where to find this information. You can let the computer run DHCP and the Windows server will give you the data after the assignment is done. But if you want to assign addresses before the systems connect to the network, you are in trouble.
Observations:
After – but not before – the Windows 7 client has an IPv6 address it will show you the DUID and the IAID for each interface.
The Linux DHCPv6 server showed a very strange piece of data that is not easy to relate to the DUID and IAID for the host in the dhcp leases file. This is not good.
In OS/X, we could not figure out how to find the DUID and IAID used in DHCPv6. Surely Apple doesn’t want to force admins to use Wireshark to find out?
Björn, the sysadm on the site, told us that when enabling DHCPv6 on the production network there was a lot of warnings on screens about duplicate IPv6 addresses. The reason for this turned out to be that PCs are installed by distributing ghost images of a master system. Every system had the same DUID and got the same IPv6 assignment. The DUID is in the Windows Registry and can be removed with a manual operation. This should be done before creating a ghost image, so that when the copies are booted on new machines, new and unique DUIDs will be created. We hope that there are tools that can do this automatically in a network.
reg delete HKLM\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters /f /v Dhcpv6DUID
http://ipv6friday.org/blog/2012/01/lab-report/
————————————————————————————————-
What is a DUID?
DUID stands for “DHCP Unique Identifier”. It is used only with DHCPv6. Each client and server that supports DHCPv6 has a DUID. It is basically the Link Layer address of the node, plus some additional stuff. There are several types of DUID, based on what “other stuff” is added. There are three DUID types defined in RFC 3315 (DHCPv6 specification), but others may be defined in the future. The three existing types are:
1 – DUID-LLT – Link Layer address plus timestamp
2 – Vendor assigned unique ID based on Enterprise Number
3 – Link Layer address
Type 1 DUIDs (DUID-LLT) contain a 16-bit field with the DUID type (1), a 16 bit hardware type field (1 for Ethernet), a 32 bit timestamp field, and a variable length Link Layer address field (length based on hardware type). All Windows nodes appear to use Type 1 DUIDs. The DUID on my Lawrence-PC node is 00-01-00-01-18-BA-30-56-50-46-5D-6B-7A-54. The last 6 fields are that node’s MAC address.
The hardware type is one of the codes from RFC 826. Ethernet is type 1.
The timestamp is supposed to be the time that the DUID was generated, in seconds since midight UTC, January 1, 2000, modulo 232. In practice, many of the DUIDs I’ve seen have some unusual values. For example, my ws3 server (WS2008R2) uses the timestamp Jun 30, 2042, 16:44:02. My ws4 server (also WS2008R2) uses the timestamp Jun 10, 2042, 16:00:04. My Lawrence-PC node (Windows 7) uses the timestamp Feb 22, 2013, 21:34:14 (this might have been when I installed the OS, I’m not sure). I’m fairly certain the timestamps on the WS2008R2 boxes are bogus (although its possible they might be valid if you subtract 30 years). Regardless, it appears that no one depends on these timestamps being accurate. This may have been an idea that seemed really good at the time the specification was written, but isn’t actually used in practice.
Type 2 DUIDs (DUID-EN) have a 32 bit enterprise number (registered with IANA) identifying the enterprise that created the DUID, followed by a variable length identifier issued by the enterprise. I have never seen a Type 2 DUID in practice.
Type 3 DUIDs (DUID-LL) contain a 16-bit field with DUID type (3), a 16 bit field with hardware type (Ethernet = 1) and a variable length field containing the device’s Link Layer address (the length depends on the hardware type). This type is recommended for devices that have a permanently connected network interface with a Link Layer address, and do not have any nonvolatile writable, stable storage. It must not be used by DHCP clients or servers that cannot tell whether or not a network interface is permanently attached to the device. I have never seen a Type 3 DUID in practice.
The client’s DUID must be specified for an Address Reservation in DHCPv6.
What is an IAID?
IAID stands for “Identity Association Identifier”. An “identity association” (IA) is a construct through which a server and a client and identify, group and manage a set of related IPv6 addresses. Each IA consists of an IAID and associated configuration information.
A client must associate at least one distinct IA with each of its network interface fro which it is to request the assignment of IPv6 addresses from a DHCPv6 server. The client uses the IAs assigned to an interface to obtain configuration information from a server for that interface. Each IA must be associated with exactly one interface.
The IAID uniquely identifies the IA and must be chosen to be unique among the IAIDs on the client. The IAID is chosen by the client. For any given use of an IA by the client, the IAID for that IA must be consistent across restarts of the DHCP client.
The IAID uniquely identifies the IA and must be chosen to be unique among the IAIDs on the client. The IAID is chosen by the client. For any given use of an IA by the client, the IAID for that IA MUST be consistent across restarts of the DHCP client.
For example, the IAID on my Lawrence-PC node is 218628135.
The IAID must be supplied for an Address Reservation in DHCPv6.
Address Reservation with DHCPv6
Just like with DHCPv4, you can create an “address reservation” in DHCPv6. It is a bit more difficult in DHCPv6 because you don’t link it to a node’s MAC address, but to the node’s DUID and IAID (see above). The easy way to create an address reservation with the Microsoft DHCPv6 server is to elevate an existing address assignment to a reservation. To elevate an existing address assignment, find the one you want to elevate under Address Leases (in the Microsoft DHCP management tool), right click, and select “Add to Reservation”. No additional information is required (the address assignment already contains the DUID and IAID). If you do this, the new reservation should appear under Reservations. In the future, any time that node requests an IPv6 address from DHCPv6, it should get the reserved address.
To create a reservation manually (as opposed to elevating an existing assignment), you will need an unused IPv6 global unicast address and the DUID and IAID of the node you want to make a reservation for. You can find the DUID and IAID values for any Microsoft node with “ipconfig”, under DHCPv6 IAID and DHCPv6 Client DUID. These appear in ipconfig only if Managed Address is enabled (either from Router Advertisement M flag, or manual setting of Managed Address option with netsh or NetConf).
Right click on Reservations (under IPv6 / Scope) and select “New Reservation”. In the resulting dialog box, enter the nodename after “Reservation”, supply the address suffix of the address to be reserved (the prefix is already supplied, based on the scope information); the DUID; and the IAID. All reserved addresses are automatically removed from the available address pool.
http://www.sixscape.com/joomla/sixscape/index.php/ipv6-training-certification/ipv6-forum-official-certification/ipv6-forum-network-engineer-silver/network-engineer-silver-network-autoconfiguration/dhcpv6-dynamic-host-configuration-protocol-for-ipv6
—————————————————————————————
What is SMBIOS GUID?
In computing, the System Management BIOS (SMBIOS) specification defines data structures (and access methods) that can be used to read information stored in the BIOS of a computer. Circa 1999, it became part of the domain of the Distributed Management Task Force (DMTF). Before this integration, SMBIOS functionality had the name DMIBIOS, since it interacted with Desktop Management Interface (DMI). At approximately the same time Microsoft started to require that OEMs and BIOS vendors support the interface/data-set in order to have Microsoft certification.
Microsoft specifies WMI as the preferred mechanism for accessing SMBIOS information from Microsoft Windows.[3]
On Windows systems that support it (XP and later), some SMBIOS information can be viewed with either the WMIC utility with ‘BIOS’/’MEMORYCHIP’/’BASEBOARD’ and similar parameters, or by looking in the Windows Registry under HKLM\HARDWARE\DESCRIPTION\System
http://en.wikipedia.org/wiki/System_Management_BIOS
To obtain the SMBIOS GUID from a PC having the problem, use one of the below methods:
At a command prompt, run the command:
wmic
When the prompt
wmic:root\cli>
appears, type in the command:
csproduct get uuid
The SMBIOS GUID for the PC should be displayed.
http://blogs.technet.com/b/system_center_configuration_manager_operating_system_deployment_support_blog/archive/2011/10/19/no-assigned-task-sequence-when-initiating-deployments-caused-by-duplicate-smbios-guids-system-uuids-in-system-center-configuration-manager-2007.aspx
0
0
B-C
https://social.technet.microsoft.com/Forums/en-US/d087eabf-d4fb-4b78-8647-0a436f897b3e/how-to-do-reservations-in-dhcp-for-ipv6-server-2012-unwanted-dhcp-addresses-on-servers?forum=winserverNIS
0
0