IPv4 and IPv6 Configurable Registry Settings (Compact 2013)

Article
11/04/2015

3/26/2014

The registry settings described in this section apply to both IPv4 and IPv6. Because the TCP implementations for IPv4 and IPv6 are separate, you might notice slightly different behavior when you configure these parameters for IPv4 and IPv6.

Configurable Settings

The following registry settings are configurable settings located under the HKEY_LOCAL_MACHINE\Comm\Tcpip\ registry branch. For most of the global TCP/IP registry settings, restarting the system is required for a change in any of these values to take effect.

Network adapter-specific values are listed under a subkey for each network adapter. The subkey depends on whether the system or network adapter is configured by Dynamic Host Configuration Protocol (DHCP) and whether static override values have been specified. Some adapters can have both DHCP and statically configured values. For a change in any of these values to take effect, you usually have to change a network adapter, reinsert a network adapter, or call the appropriate IP Helper functions.

Global TCP/IP Registry Settings

The following table shows the configurable registry values for the HKEY_LOCAL_MACHINE\Comm\Tcpip\Parms registry key

Name: type	Description
DefaultTTL : REG_DWORD	Default setting is 128. The range is 1-255. This specifies the Time to Live (TTL) value in the header of outgoing IP packets. The TTL determines how long an IP packet that has not reached its destination can remain on the network before it is discarded. For more information, see Time to Live in RFC 791 and Hop Limit in RFC 2460.
DisableIPSourceRouting : REG_DWORD	The default configuration for IPv4 networks is 1. The range is 0 - 2. IP source routing determines the IP route that a datagram follows through the network. A value of 0 indicates no additional protection, source routed packets are enabled. A value of 1 indicates medium protection, source routed packets are ignored when IP forwarding is enabled. A value of 2 indicates the highest protection, source routing is completely disabled.
ArpRetryCount : REG_DWORD	Default setting is 3. The range is 1-3. This value determines how many times TCP sends an Address Request Packet (ARP) for its own address, known as a gratuitous ARP, when the service is installed. TCP sends a gratuitous ARP to determine whether the IP address to which it is assigned is already being used on the network.
EnableICMPRedirect : REG_DWORD	Default setting is 1 (True). This value can be either 0 (False) or 1 (True) to indicate if Windows should enable ICMP redirects. Setting this value to 1 causes Windows to change the route table in response to an Internet Control Message Protocol (ICMP) redirect message that is sent to it by a network device, such as a router.
IGMPLevel : REG_DWORD	Default setting is 2. This value can be set to 0, 1, or 2. It indicates to what extent the system can support IP multicasting and how fully it participates in the Internet Group Management Protocol (IGMP). Setting this value to 0 allows the system to provide no multicast support. Setting this value to 1 enables the system to send IP multicast packets, but not to receive them. Setting this value to 2 enables the system to send IP multicast packets and to participate fully in the IGMP to receive multicast packets.
IGMPVersion : REG_DWORD	Default setting is 4. This value can be set to 3 or 4 to specify the version of IGMP to use. For desktop compatibility, set this value to the desired version plus one.
EnableAddrMaskReply: REG_DWORD	Default setting is 0 (False). This value can be either 0 (False) or 1 (True). A setting of 0 determines whether the computer responds to the ICMP address mask requests by sending ICMP address mask replies.
EnableBcastArpReply : REG_DWORD	Default setting is 1 (True). This value can be either 0 (False) or 1 (True). A setting of 1 enables a multicast Media Access Controller (MAC) address in the Sender Hardware Address (SHA) field in an ARP reply message. This enables communication with a Network Load Balancing (NLB) cluster that is operating in multicast mode. If a host on the same subnet as the NLB cluster does not support use of a multicast MAC address in the SHA field of an ARP reply, communication with the cluster is not possible.
DisableDHCPMediaSense: REG_DWORD	Default setting is 0 (False). This value can be either 0 (False) or 1 (True). This setting controls the behavior of Media Sensing. By default, Media Sensing events trigger a DHCP client to take an action. For example, when a connect event occurs, the client tries to obtain a lease. When a disconnect event occurs, the client may invalidate the interface and routes. If you set this value data to 1, DHCP clients ignore Media Sensing events.
DisableMediaSenseEventLog: REG_DWORD	Default setting is 0 (False). This value can be either 0 (False) or 1 (True). A setting of 0 disables the logging of DHCP Media Sense events. By default, Media Sense events (connection/disconnection from the network) are logged in the event log for troubleshooting.
EnableMulticastForwarding: REG_DWORD	Default setting is 0 (False). This value can be either 0 (False) or 1 (True). The setting determines whether the computer forwards IP multicasts. A setting of 1 enables hosts to send a datagram to multiple recipients in a single operation. The originating host transmits the IP multicast datagram as a local network multicast to all immediately neighboring members of the destination host group. Then, multicast routers on the local network forward the datagram to all other networks. A setting of 0 specifies that the computer does not forward IP multicasts.
IPEnableRouter: REG_DWORD	Default setting is 0 (False). This value can be set to either 0 (False) or 1 (True) to specify if IP routing is enabled. Setting this value to 1 (True) causes the system to route IP packets between the networks to which it is connected. Caution: Enabling routing can potentially compromise network security.
OverrideDefaultAddressSelection : REG_DWORD	By default, Windows systems follow RFC 3484 for destination IP address selection, which does not honor Domain Name System (DNS) round robin. Use this setting to disable subnet prioritization.
IPAutoconfigurationSubnet : REG_SIZE	Default setting is 169.254.0.0. This value determines the subnet address that IP autoconfiguration uses to assign an IP address to an interface.
IPAutoconfigurationMask : REG_SZ	Default setting is 255.0.0.0. This value stores the subnet mask that the IP autoconfiguration feature assigns to the client.
ArpUseEtherSNAP : REG_DWORD	Default setting is zero (0). This value can be set either to 0 (False) or 1 (True) to specify if Ethernet transmission uses subnework access protocol (SNAP) encoding. Setting this value to 1 forces TCP/IP to transmit Ethernet packets by using 802.3 SNAP encoding. By default, the stack transmits packets in DIX Ethernet format. It will always receive both formats.
MaxUserPort: REG_DWORD	Default setting is 5000. The range is 5,000-65,534 (port number). This value specifies the highest user port number that TCP can assign when an application requests an available port from the system.
AutoCfg : REG_DWORD	This value can be set either to 0 (False) or to 1 (True) to specify whether Automatic IP is enabled. This value behaves as the default value for the adapter-specific setting of the same name. For example, setting this value to 1 indicates that all adapters will use having Automatic IP enabled.
EnableDHCP : REG_DWORD	IPv4 only. Set by DHCP. This value can be either 0 (False) or 1 (True), to specify whether DHCP is enabled. This value behaves as the default setting for the adapter-specific value of the same name. For example, setting this value to 1 indicates that all adapters will use having Automatic IP enabled.
EnablePMTUDiscovery : REG_DWORD	Default setting is 1 (True). The default is 0. The default setting of 0 specifies that TCP uses a fixed MTU of 576 bytes. A setting of 1 specifies that TCP tries to detect the actual MTU, or largest packet size, over the path of a remote host.
TcpUseRFC1122UrgentPointer : REG_DWORD	Default setting is 0. This value can be either 0 (False) or 1 (True). A setting of 0 indicates that TCP uses the mode used by systems derived from Berkeley Software Distribution (BSD) for delivering urgent data. A setting of 1 indicates that TCP uses the specification in RFC 1122, Requirements for Internet hosts-communication layers, for urgent data. The two modes interpret the urgent pointer in the TCP header and the length of the urgent data differently. The two modes do not interoperate.
DisableTaskOffload : REG_DWORD	Default setting is 0 (False). This value can be either 0 (False) or 1 (True). A setting of 1 disables the offloading of processor tasks to the network adapter. Offloading some tasks to the network adapter leaves the processor free for tasks that only it can perform. Caution: Use of DisableTaskOffload will decrease performance.
TcpMaxDataRetransmissions: REG_DWORD	Default setting is 5. The valid range for this value is 0-0xFF (hexadecimal). This value specifies the number of times that TCP retransmits a single data segment (does not include connection request segments) before canceling the connection. Note: On TCP/IPv6 networks, Neighbor Discovery (ND) can require a minute to fail-over to another router. To enable TCP connections to survive long enough so that this fail-over can complete, the TcpMaxDataRetransmissions setting does not take effect when it is below a certain value. Retransmissions will continue for one minute or until the required number of retransmissions occur, whichever time is greater.
KeepAliveTime: REG_DWORD	Default setting is 7,200,000 msec (two hours). This value specifies how frequently TCP sends keep-alive transmissions. If the remote system is still reachable and functioning, it will acknowledge the keep-alive transmission. Keep-alive packets are not sent by default. An application can enable this setting for a particular connection. The valid range for this value is 1-0xFFFFFFFF (hexadecimal).
TcpTimedWaitDelay : REG_DWORD	Default setting is 240. The valid range for this value is 30 to 300 milliseconds. This value determines the length of time that a connection stays in the TIME_WAIT state when it is closed. As long as a connection is in the TIME_WAIT state, the socket pair cannot be reused.
TcpFinWait2Delay : REG_DWORD	Default setting is 240 seconds. The range is 30-300. This value controls how many seconds that a TCP connection waits before it is forced to close after the shutdown (s, SD_SEND) function is called. If the TCPFinWait2Delay value does not exist, you must create it as a REG_DWORD registry value.
EnablePMTUBHDetect : REG_DWORD	Default setting is 0 (False). This value can be either 0 (False) or 1 (True). A setting of 0 disables block hole detection. TCP tries to detect black hole routers during the Path MTU (maximum transmission unit) discovery process. Enabling black hole detection increases the maximum number of times TCP retransmits a given segment. If the value of this setting is 1, TCP recognizes when it has transmitted the same segment several times without receiving an acknowledgement. It reduces the maximum segment size (MSS) to 536 bytes, and it sets the Don’t-Fragment bit. If, therefore, receipt of the segment is acknowledged, TCP continues this practice in all subsequent transmissions on the connection.
EnableWsd : REG_DWORD	Default setting is 1. This value can be either 0 (False) or 1 (True). Windows scaling can automatically change its own TCP window auto-tuning behavior regardless of any user setting. A setting of 1 enables Windows scaling.
QualifyingDestinationThreshold : REG_DWORD	The value is not set by default. Set the value to a low number, such as 3, to close a connection if a destination host is unreachable.
TcpSendQueueDelay : REG_DWORD	Default setting is 4. This value designates the time (in milliseconds) that the TCP send queue should wait to batch outgoing packets together. By batching the packets together, TCP outgoing throughput can increase for many scenarios. Value 0 will disable this feature. A larger value will allow the TCP send queue more time to batch packets together. However, this can also increase latency for outgoing packets.
ResolverRetryCount : REG_DWORD	Default setting is 2. This value specifies the number of times that name resolution tries to resolve a name with DNS or WINS. This value can be any positive integer greater than or equal to 1.
NoIdleIfAdapter : REG_DWORD	Default setting is 0 (False). This value specifies whether the device goes into Idle mode during TCP/IP communications, and is independent of the NoIdleIfConnected value. Setting this value to 1 (True) keeps the device from going into Idle mode as long as there is a network adapter being used in the device. Setting this value to 0 (False) enables a device to be suspended when a network adapter is being used.
NoIdleIfConnected : REG_DWORD	Default setting is 1 (True). This value specifies whether the device goes into Idle mode during TCP/IP communications, and is independent of the NoIdleIfAdapter value. Setting this value to 0 (False) enables the device to enter Idle mode even in the middle of communication with another device, or over loopback. Setting this value to 1 (True) keeps the device from going into Idle mode and makes the device maintain an active TCP/IP connection, even if there is no active network adapter.
Tcp1323Opts	By default, this value does not initiate options but provides them if it is requested. This value controls RFC 1323 timestamps and window-scaling options. Timestamps and window scaling are enabled by default, but can be manipulated with flag bits. Bit 0 controls window scaling, and bit 1 controls timestamps. In current implementation, the first bit is ignored. This value can have the following settings: 0 Disables RFC 1323 options 2 Enables timestamps only

IPv6s Settings

The following table contains IPv6 settings located in the HKEY_LOCAL_MACHINE\Comm\Tcpip6\Parms registry key.

Name: type	Description
UseTemporaryAddresses : REG_DWORD	Boolean value that specifies whether temporary addresses should be used. Default setting is true (1).
EnableDHCPv6 : REG_DWORD	Boolean value that indicates whether the DHCPv6 client is enabled.

Adaptor- and Interface-specific Settings

You can configure the TCP/IP implementation for a specific network adapter that is bound to TCP/IP through the registry. The following table shows the adapter-specific values for the HKEY_LOCAL_MACHINE\Comm\<Adapter Name>\Parms\Tcpip subkey.

Name : type	Description
MTU : REG_DWORD	Default setting is 1 (True). The default is 0. The default setting of 0 specifies that TCP uses a fixed MTU of 576 bytes. A setting of 1 specifies that TCP tries to detect the actual MTU, or largest packet size, over the path of a remote host.
IPAutoconfigurationEnabled : REG_DWORD	Default setting is 1. This value can be either 0 (False) or 1 (True). A setting of 1 enables IP autoconfiguration for this interface. Autoconfiguration enables TCP/IP to configure an interface even when it cannot locate a DHCP server. If TCP/IP cannot locate a DCHP server, it configures the interface by using IP addresses from the Microsoft reserved Class B network (169.254.0.0), subnet mask 255.255.0.0. During autoconfiguration, TCP/IP continues trying to locate a DHCP server, and it abandons autoconfiguration if it finds one.
AutoCfg : REG_DWORD	This value can be set either to 0 (False) or to 1 (True) to specify whether Automatic IP is enabled. This value behaves as the default value for the adapter-specific setting of the same name. For example, setting this value to 1 indicates that all adapters will use having Automatic IP enabled.
AutoInterval : REG_DWORD	Default setting is 300. This value specifies the time interval, in seconds, used to verify that a DHCP server is available to configure adapter settings for a device, for example, IP Address, SubnetMask, default gateway, DNS and WINS servers.
AutoIP : REG_SZ	This value specifies the last known AutoIP address that is used by the device. If there is no value present, a new IP address is generated.
AutoMask : REG_SZ	Default setting is 255.255.0.0. This value specifies the default subnet mask for Automatic IP.
AutoSubnet : REG_SZ	Default setting is 169.254.0.0. This value specifies the default subnet for Automatic IP.
DefaultGateway : REG_MULTI_SZ	This value specifies the list of gateways that must be used to route packets that are not destined for a subnet to which the device is directly connected, and for which a more specific route does not exist. This value can be a set of valid IP addresses. This value is configurable from the Network Connections UI. This value overrides the DhcpDefaultGateway value. Because there is only one active default gateway for the device at any time, adding multiple addresses is only useful for redundancy.
DhcpConstantRate : REG_DWORD	This value can be either 0 (False) or 1 (True) to specify whether DHCP packets are sent at a constant rate, or a rate that is backed off exponentially. When this value is set to 1, the DHCP retransmission algorithm improves performance in wireless scenarios.
DhcpDirectRenewal : REG_DWORD	Default setting is 0. If this value is 0, DHCP traffic is broadcast. If this value is 1, the DHCP client sends request packets to the DHCP server.
DhcpFirstRetransmitInterval : REG_DWORD	Default setting is 500 milliseconds. The value can be set to any positive integer less than 8000 milliseconds. The DHCP DISCOVER message is sent with the BROADCAST flag by default. If there is no response, the DHCP DISCOVER message is toggled to have a UNICAST flag and resent. This loop continues six times: three messages with the BROADCAST flag and three messages with the UNICAST flag. The difference between each retry starts with 500 milliseconds and is doubled every time with a maximum wait time of 8000 milliseconds. Because the DHCP DISCOVER packet is sent out first with the BROADCAST flag and toggles to UNICAST based on the previous retry, both scenarios are handled.
DhcpGlobalInitDelayInterval : REG_DWORD	Default setting is 0. This value specifies the global initial delay, in milliseconds, between DHCP packets that are sent. This value can be set to any positive integer.
DhcpInitDelayInterval : REG_DWORD	Default setting is 0. This value specifies the initial delay, in milliseconds, between DHCP packets that are sent. This value can be set to any positive integer. This value overrides DhcpGlobalInitDelayInterval.
DhcpMaxRetries : REG_DWORD	Default value is 6: three retries for BROADCAST flag and 3 for UNICAST flag. This value defines the maximum number of attempts made to obtain a DHCP address. It can be any positive integer. For a remotely administered device, setting a large value, such as 0xfffffffff, causes the DHCP client to be more persistent and recover after a temporary network outage.
DhcpMaxRetransmitInterval : REG_DWORD	Default setting is 64000 milliseconds. Must be set in the range from 500 through 64000 milliseconds. See also DhcpFirstRetransmitInterval.
DhcpNoMacCompare : REG_DWORD	Default setting is 0. If this value is set, the MAC address in DHCP packets returned from the server is compared to the local interface. If the address does not match, the packet is discarded.
DhcpOptions : REG_BINARY	The valid range for this value is 1-0xFF (hexadecimal). This value specifies RFC 2132-compliant DHCP option value names for the server to retrieve. By default, Windows Embedded Compact 2013 queries for the IP address, default gateway, subnet mask, DNS server, and WINS server. The values that the server retrieves are not put under DhcpOptions unless you create the value names.
DhcpSendOptions : REG_BINARY	This value is not set by default. It specifies options to copy to the DHCP packet and send to the DHCP server. These options must be valid and recognizable by the server.
EnableDhcp : REG_DWORD	This value can be either 0 (False) or 1 (True), to specify whether DHCP is enabled. This value behaves as the default setting for the adapter-specific value of the same name. For example, setting this value to 1 indicates that all adapters will use having Automatic IP enabled.
IPAddress : REG_MULTI_SZ	This value is not set by default. This value specifies the IP addresses of the IP interfaces to be bound to the adapter. This value is configurable from the Network Connections UI.
SubnetMask : REG_MULTI_SZ	This value is not set by default. It specifies the subnet masks that must be used with the IP interfaces bound to the adapter. This value can be any set of valid IP addresses. This value is configurable from the Network Connections UI).
TcpAckFrequency : REG_DWORD	Default setting is 2. Range 0-255. Determines the number of TCP acknowledgments (ACKs) that will be outstanding before the delayed ACK timer is ignored.
TcpDelAckTicks : REG_DWORD	Default setting is 2. This value can be any number from 2 to 6. It specifies the number of milliseconds to use for the delayed-ACK timer on a per-interface basis. By default, the delayed-ACK timer is 200 milliseconds.
UseZeroBroadcast : REG_DWORD	Boolean value that determines whether IP uses zeros broadcasts or ones broadcasts. Most systems use ones broadcasts, but some systems, such as those derived from Berkeley Software Distribution (BSD) implementations, use zeros broadcasts. Systems using different broadcasts do not communicate well on the same network. When set to FALSE (0) uses ones broadcasts. The ones local broadcast address is 255.255.255.255 When set to TRUE (1) uses zeros broadcasts. The zeros local broadcast address is 0.0.0.0.
PerformRouterDiscovery : REG_DWORD	Boolean value that determines whether the device performs router discovery on this interface.
WINS : REG_MULTI_SZ	This value is not set by default. This value can be set to any valid IP address that indicates the WINS name server. Two WINS servers can be listed.
WinsBroadcastTimeOut : REG_DWORD	Default setting is 500. This value specifies the length of time, in milliseconds, that name resolution waits for a response to the IP subnet broadcast.
WinsTimeOut : REG_DWORD	Default setting is 2000. This value specifies the length of time, in milliseconds, that name resolution waits for a response from the WINS server.
DNS : REG_MULTI_SZ	This value is not set by default. It specifies the list of valid IP addresses of available DNS servers.
Domain : REG_SZ	This value is not set by default. It specifies domain name information available from a DHCP message from the DHCP server on the network. For example, DHCP: Domain Name = example.microsoft.com.
DNSTimeOut : REG_DWORD	Default value is set to 3000. This value specifies the length of time, in milliseconds, that name resolution waits for a response from the DNS server. Done by AFD
DontAddDefaultGateway : REG_DWORD	Default setting is 0. This value can be either 0 (False) or 1 (True) to indicate if a default gateway should be installed for an adapter. When you install PPTP, a default route is installed for each LAN adapter. You can disable the default route on an adapter by setting this value to 1. After making the setting, you might have to configure static routes for hosts that are reached by using a router other than the default gateway.
RebindOnResume : REG_DWORD	This value is not set by default. It specifies whether rebind on resume is enabled. A value of 1 indicates that NDIS unbinds and binds the adapter when a device resumes from a suspended state. This unbind and rebind process causes DHCP to renew the IP address for the adapter. This value can be used by an adapter that does not support media indication status.
DisablePowerManagement : REG_DWORD	Default setting is 0 (False). The setting indicates whether NDIS disables power management. A value of 0 indicates that NDIS registers power-manageable adapters. A value of 1 indicates that NDIS does not register the adapters, thereby disabling power management.
ResetOnResume : REG_DWORD	Default setting is 0. This value indicates whether NDIS unloads the miniport drivers during system suspend and resume, assuming that the card is not physically removed. Done by dhcpv6, not in nsi. This key must be set for quick connect. This key is located under [HKEY_LOCAL_MACHINE\Comm\AR6K_SD1\Parms] If this value is set to 1, the miniport driver remains loaded. If this value does not exist or is set to 0, and the card is not physically removed, NDIS unloads and then reloads the driver during the resume process. This value requires the driver to have support from the OAL. The miniport driver must support MiniportResetHandler. Note: Multicast membership is always preserved for PCI adapters.
DisconnectOnHalt : REG_DWORD	This registry entry configures the WiFi behavior and is located under the HKEY_LOCAL_MACHINE\Comm\<Adapter>\Parms\ExtSTA registry subkey. The <Adapter> placeholder represents the RTL WIFI adapter card (For example, PCI\rtlnwifi1). This key must be set for quick connect.
Ipv6Address	IP address for IPv6 only.
ResetOnSuspendResume: REG_DWORD	This registry entry configures the WLAN AutoConfig behavior and is located under the HKEY_LOCAL_MACHINE\Services\WLANSVC registry subkey. `[HKEY_LOCAL_MACHINE\Services\WLANSVC] "ResetOnSuspendResume"=dword:0 "ReleaseIPOnSuspendResume"=dword:1 "PwrCtrlOnSuspendResume"=dword:0 "ConnectStateCtrlOnSuspendResume"=dword:4 "ActivePowerMgmt"=dword:0 "IntersilCard"=dword:1`
ReleaseIPOnSuspendResume : REG_DWORD	Releases the IP address, and forces a DHCP allocation during suspend and resume. This will force a NETDown, and NETUp indication. Default is 1. `[HKEY_LOCAL_MACHINE\Services\WLANSVC] "ReleaseIPOnSuspendResume"=dword:1`
PwrCtrlOnSuspendResume : REG_DWORD	Forces power off during suspend and power on during resume for hardware, regardless, of the power state. `[HKEY_LOCAL_MACHINE\Services\WLANSVC] "PwrCtrlOnSuspendResume"=dword:0`
ConnectStateCtrlOnSuspendResume : REG_DWORD	During resume speeds up the connection process and skips some state machine sequences. This key has the following settings. Default is 4 for quick connect. DWORD:0 - NOT_SET – this will leave the state machine in the same state it was left in prior to suspend and resume. DWORD:1 - DISCONNECTED– this will start the state machine in the disconnected state. DWORD:2 - CONNECTED – this will start the state machine in the connected state. DWORD:3 - ROAMING – this will start the state machine in the roaming state. DWORD:4 - QUICK_CONNECT – this will perform the quick connect. `[HKEY_LOCAL_MACHINE\Services\WLANSVC] "ConnectStateCtrlOnSuspendResume"=dword:4`
ActivePowerMgmt : REG_DWORD	Reduces the scan interval, puts the connection into idle state, saves power. `[HKEY_LOCAL_MACHINE\Services\WLANSVC] "ActivePowerMgmt"=dword:0`
IntersilCard : REG_DWORD	Fixes intersil card connection issues. Default is 0: generated with sysgen using BSP_NIC_AR6K_NWF, and BSP_NIC_ISLP2NDS_PCMCIA `[HKEY_LOCAL_MACHINE\Services\WLANSVC] "IntersilCard"=dword:1`

Hosts Configurable Settings

The host name can be configured through the HKEY_LOCAL_MACHINE\Comm\Tcpip\Hosts subkey. When an application calls gethostbyname (deprecated) or getaddrinfo, the registry is queried first, before a DNS or WINS request is sent. If the host name is found in the registry, the registry values are returned. The following table shows the values for the HKEY_LOCAL_MACHINE\Comm\Tcpip\Hosts\<Host Name> subkey.

Name: type	Description
Aliases : REG_MULTI_SZ	This value specifies the aliases by which the host is known.
ExpireTime : REG_BINARY	This value specifies the expiration time for the host. The length of this value is 8 bytes. If the current time, obtained by calling GetCurrentFT, exceeds the amount set for ExpireTime, the complete Host Name subkey is deleted the next time that WSAAsyncGetHostByName is called.
ipaddr : REG_BINARY	This value specifies the TCP/IPv4 addresses associated with the host name. The length of this value is 4 bytes per address.
ipaddr6 : REG_BINARY	This value stores the TCP/IPv6 addresses associated with the host name. The length of this value is 20 bytes per address (16 bytes for address and 4 bytes for scope ID).

AFD Settings

The following table shows the values for the HKEY_LOCAL_MACHINE\Comm\AFD subkey for the Windows Embedded Compact Protocol Manager (AFD).

Name: type	Description
STACKS : MULTI_SZ	By default, this value is not set and all protocol stacks are loaded during device startup. You can set this value to prevent the Bluetooth stack from loading during startup. If the key HKEY_LOCAL_MACHINE\Comm\AFD\STACKS is there, and the value string does not contain “btd”, Bluetooth wireless technology will not be loaded. If the key HKEY_LOCAL_MACHINE\Comm\AFD\STACKS is not there, Bluetooth wireless technology will be loaded by default.
LLMNRv6Address : REG_SZ	Default setting is FF02:0:0:0:0:0:1:3. The IPv6 address to use for Link-Local Multicast Name Resolution (LLMNR) queries.
LLMNRPort : REG_DWORD	Default setting is 5353. The port to use for LLMNR queries over TCP and UDP. Done in AFD, not in nsi.

STACKS : MULTI_SZ

By default, this value is not set and all protocol stacks are loaded during device startup. You can set this value to prevent the Bluetooth stack from loading during startup.

If the key HKEY_LOCAL_MACHINE\Comm\AFD\STACKS is there, and the value string does not contain “btd”, Bluetooth wireless technology will not be loaded.

If the key HKEY_LOCAL_MACHINE\Comm\AFD\STACKS is not there, Bluetooth wireless technology will be loaded by default.

LLMNRv6Address : REG_SZ

Default setting is FF02:0:0:0:0:0:1:3. The IPv6 address to use for Link-Local Multicast Name Resolution (LLMNR) queries.

LLMNRPort : REG_DWORD

Default setting is 5353. The port to use for LLMNR queries over TCP and UDP. Done in AFD, not in nsi.

Device Name Settings

The following table shows the values for the HKEY_LOCAL_MACHINE\Ident registry key. This key identifies the device. A configurable Name value is defined for this key, but the other settings are non-configurable.

Important

This registry key must not be changed except by the OEM, and is read-only for all applications. If it is changed by an application, the WINS registration with a new name will not complete correctly.

Name : type	Description
Desc : REG_SZ	This value provides a description for the device.
Name : REG_DWORD	This value provides the device name, supplied by the OEM.
OrigName : REG_DWORD	This value stores the name of the device at the time when the device was started. When the device is started, this value is automatically created and set to WinCE. If a Name value exists, it is copied to the OrigName value. Done in AFD, not in nsi. An application can only modify the OrigName value by using sethostname.

Desc : REG_SZ

This value provides a description for the device.

Name : REG_DWORD

This value provides the device name, supplied by the OEM.

OrigName : REG_DWORD

This value stores the name of the device at the time when the device was started. When the device is started, this value is automatically created and set to WinCE. If a Name value exists, it is copied to the OrigName value. Done in AFD, not in nsi.

An application can only modify the OrigName value by using sethostname.