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Windows TCP/IP Registry Entries

This article was previously published under Q158474
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Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows

The value entries that are described in this article do not normally exist in the Windows registry; they must be added to the following registry key:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\MSTCP

Values

  • BroadcastAddress = broadcast address in hexadecimal

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies the address to use for NetBIOS name query broadcasts. Thedefault is based on the IP address and the subnet mask.
  • BcastNameQueryCount = integer

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies the number of times the system will retry NetBIOS name querybroadcasts. The default is 3.
  • BcastQueryTimeout = milliseconds

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies the period of time the system will wait before timing outbroadcast name queries. The minimum value is 100. The default is 750.
  • BSDUrgent = 0 or 1

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    If this value is 1, it specifies that Microsoft TCP/IP is to treaturgent data the way some UNIX systems do (with a maximum of 1 byte ofurgent data, for example). If this value is 0, it specifies that thestack is to handle urgent data as specified by RFC 1122. The default is 1.
  • CacheTimeout = milliseconds

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies how long NetBIOS names are cached. The minimum is 60,000milliseconds (1 minute). The default is 360,000 milliseconds (6 minutes).
  • DeadGWDetect = 0 or 1

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies whether Microsoft TCP/IP will use another gateway if thecurrent default gateway seems to be down. The default is 1.
  • DefaultRcvWindow = 16-bit number

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies the default receive window advertised by TCP. The default is8192.
  • DefaultTOS = 8-bit number

    Data Type: DWORD

    Specifies the default type of service (TOS) for IP packets initiated byMicrosoft TCP/IP. The default is 0.
  • DefaultTTL = 8-bit number

    Data Type: String

    Specifies the default time to live (TTL) for IP packets from MicrosoftTCP/IP. The default is 32.
  • DnsServerPort = port

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies which DNS server port to send queries to when resolving a nameusing DNS. The default is 53.
  • EnableProxy = 0 or 1

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    If this value is 1, it specifies that this computer is a WINS proxyagent. The default is 0.
  • IGMPLevel = 0, 1, or 2

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies the level of support allowed for IP multicast, correspondingto the levels in RFC 1112. The default is 2.
  • InitialRefreshT.O. = milliseconds

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies the interval over which to contact WINS to refresh the name.The minimum is 16 minutes, and the maximum is approximately 50 days(0xFFFFFFFF). The default is 960,000 milliseconds (16 minutes).
  • KeepAliveTime = milliseconds

    Data Type: DWORD
    For Windows 98, the Data Type is a String Value.

    Specifies the connection idle time in milliseconds before TCP will beginsending keepalives, if keepalives are enabled on a connection. Thedefault is 2 hours (7,200,000).
  • KeepAliveInterval = 32-bit number

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies the time in milliseconds between retransmissions ofkeepalives, once the KeepAliveTime has expired. Once KeepAliveTime hasexpired, keepalives are sent every KeepAliveInterval milliseconds untila response is received, up to a maximum of MaxDataRetries before theconnection is terminated. The default is 1 second (1000).
  • LmhostsTimeout = milliseconds

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies the period of time the system will wait before timing out whenseeking LMHOSTS for name resolution. The minimum value is 1000 (1second). The default is 10,000 (10 seconds).
  • MaxConnections = 32-bit number

    Data Type: String

    Specifies the maximum number of concurrent connections. The default is 100.
  • MaxConnectRetries = Number

    Data Type: String

    Specifies the number of times a connection attempt (SYN) will beretransmitted before giving up. The initial retransmission timeout is 3seconds, and it is doubled each time up to a maximum of 2 minutes. Thedefault is 3.
  • MaxDataRetries = 32-bit number

    Data Type: String

    Specifies the maximum number of times a segment carrying data or an FINwill be retransmitted before the connection is terminated. Theretransmission timeout itself is adaptive and will vary according tolink conditions. The default is 5.
  • NameServerPort = port

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies the UDP port on the name server to which to send name queriesor registrations. The default is 137.
  • NameSrvQueryCount = integer

    Data Type: String

    Specifies the number of times the system will try to contact the WINSserver for NetBIOS name resolution. The default is 3.
  • NameSrvQueryTimeout = milliseconds

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies how long the system waits before timing out a name serverquery. The minimum is 100. The default is 750.
  • NameTableSize = integer

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies the maximum number of names in the NetBIOS name table. Theminimum allowable value is 1 and the maximum is 255. The default is 17.
  • NodeType = 1, 2, 4, or 8

    Data Type: String

    Specifies the mode of NetBIOS name resolution used by NetBIOS overTCP/IP, where 1 = b-node, 2 = p-node, 4 = m-node, and 8 = h-node. Thisvalue can be configured using DHCP. The default is 1 (b-node) if novalue is specified; if WINS servers are specified and NodeType is not,the default is 8 (h-node).
  • PMTUBlackHoleDetect = 0 or 1

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies whether the stack will attempt to detect Maximum TransmissionUnit (MTU) routers that do not send back ICMP fragmentation-neededmessages. Setting this parameter when it is not needed can causeperformance degradation. The default is 0.
  • PMTUDiscovery = 0 or 1

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies whether Microsoft TCP/IP will attempt to perform path MTUdiscovery as specified in RFC 1191. The default is 1.
  • PrioritizeRecordData 0 or 1

    Data Type: DWORD
    NOTE: This value is not supported in Windows 95.

    This parameter controls whether the Domain Name Resolver (DNR) sorts the addresses that are returned in response to a query for a multihomed host. By default, the DNR sorts addresses that are on the same subnet as one of the interfaces in the querying computer to the top of the list. This occurs so that a common-subnet (non-routed) IP address is given preference, when possible. The default value is 1.
  • RandomAdapter = 0 or 1

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    For a computer with multiple network adapters, specifies whether torespond with an IP address selected randomly from the set of addresseson the computer or whether to return the IP address of the adapter thatthe request came in upon. The default is 0 (not random; that is, returnthe address of the adapter that the request came in upon).
  • RoutingBufSize = 32-bit number

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies the total amount of buffer space to allocate for routingpackets. This parameter is ignored if EnableRouting=0. The default is73,216.
  • RoutingPackets = 32-bit number

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies the maximum number of packets that can be routedsimultaneously. This parameter is ignored if EnableRouting=0. Thedefault is 50.
  • SessionKeepAlive = milliseconds

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies how often to send session keepalive packets on activesessions. The minimum is 60 seconds. The default is 3600 seconds (1hour).
  • SessionTableSize = integer

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies the maximum number of sessions in the NetBIOS session table.The minimum allowable value is 1 and the maximum is 255. The default is255.
  • SingleResponse = 0 or 1

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    For a computer with multiple network adapters, specifies whether to sendall IP addresses on a name query request from WINS. If this value is 1,the system will send one address in a name query response; if 0, it willreturn all the addresses of its adapters. The default is 0.
  • Size/Small/Medium/Large = 1, 2, or 3

    Data Type: DWORD
    For Windows 98, the Data Type is a String value.

    Specifies how many buffers of various types to pre-allocate and themaximum that can be allocated, where 1 = small, 2 = medium, and 3 =large. The default is 1; the default is 3 if the WINS proxy is enabled.
  • Tcp1323Opts = 0, 1, 2 or 3

    Data Type: DWORD

    Controls RFC 1323 time stamps and window scaling options, where 0 = disable RFC 1323 options, 1 = window scale enabled only, 2 = time stamps enabled only, and 3 = both options enabled.
This section describes variables for subkeys that appear in thefollowing registry key:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\MSTCP\ServiceProvider
The following keys describe the order used to resolve host names. Alower number sets a higher priority for name resolution. These settingsare used for 16-bit Windows Sockets, which need to rely on the resolversthat are expected to take the least time. The numbers indicate thedefault values specified in Windows.

Note that the below values apply to Windows Sockets 1.1, and are not used if Windows Sockets 2.0 is installed (this is the default for Windows 98, and is an option for Windows 95).

LocalPriority = 499
HostsPriority = 500
DNSPriority = 2000
NetbtPriority = 2001

For additional information about this functionality, click the article number below to view the article in the Microsoft Knowledge Base:
170619 Windows 95 ServiceProvider Priority Values Not Applied
The entries in this section must be added to the following registry key,where n represents the particular TCP/IP-to-network adapter binding.
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Class\netTrans\000n
MaxMTU = 16-bit integer
Data Type: String

This specifies the maximum size datagram IP that can pass to a media driver. SNAP and source routing headers (if used on the media) are not included in this value. For example, on an Ethernet network, MaxMTU will default to 1500. The actual value used will be the minimum of the valuespecified with this parameter and the size reported by the media driver.The default is the size reported by the media driver.

For additional information about obtaining RFC documents, click the article number below to view the article in the Microsoft Knowledge Base:
185262 How to Obtain Request for Comments Documents from the Internet
Properties

Article ID: 158474 - Last Review: 03/27/2007 01:30:53 - Revision: 2.5

  • Microsoft Windows 95
  • Microsoft Windows 98 Standard Edition
  • Microsoft Windows 98 Second Edition
  • Microsoft Windows Millennium Edition
  • kbenv kbinfo kbnetwork KB158474
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