> Peter Lothberg writes :
> From roll(a)Stupi.SE Sun Apr 28 15:37:15 1996
> Date: Sun, 28 Apr 96 15:35:17 MET DST
> From: Peter Lothberg <roll(a)Stupi.SE>
> Subject: Windows NT and UDP checksums
> To: staff(a)ripe.net
> Message-Id: <CMM.0.90.0.830698534.roll(a)Junk.Stupi.SE>
>
>
> It was discussed at the ripe meeting, if NT could support UDP checksums or not,
> it turns out that it can...
>
> --Peter
>
> ------------------------------------------------------------------------
> REG: TCP/IP Transport Entries, PART 1
> Article ID: Q102973
> Revision Date: 05-APR-1996
>
> The information in this article applies to:
>
> - Windows NT operating system version 3.1
> - Windows NT Advanced Server version 3.1
>
>
> The article contains REGISTRY entries for the TCP/IP Transport Entries, Part
> 1. These subgroups are included:
>
> - TCP/IP Parameters Subkey Entries
> - Adapter Card Parameters for TCP/IP
>
>
> This is the first of two articles on these entries; for the other entries,
> see "TCP/IP Transport Entries, Part 2."
>
> TCP/IP TRANSPORT ENTRIES
>
> The various TCP/IP keys do not appear in the Registry unless TCP/IP is
> installed using the Network icon in Control Panel.
>
> With Registry Editor, you can modify the following parameters for the TCP/IP
> transport. This section does not include all the TCP/IP
> parameters that can be set using the Networks application in Control Panel.
>
> The startup parameters defined in this section are found in these subkeys of
> HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services:
>
> TCPIP\Parameters
> adapter_name#\Parameters\TCPIP, (where adapter_name# indicates a
> Services subkey for a network adapter
> card)
> Ftpsvc\Parameters
> NBT\Parameters
> Streams\Parameters
>
>
> Parameters for network bindings for this service are described in the
> article "NetRules Subkey Entries." See also
> IsDomainMasterBrowser in the article "Browser Service Entries."
>
> TCP/IP PARAMETERS SUBKEY ENTRIES
>
> The entries for TCP/IP parameters appear under the following Registry path:
>
> HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
>
>
> ArpCacheLife REG_DWORD Number of Seconds
>
> Default: 600 (10 minutes)
>
>
> Determines the default lifetime for entries in the ARP cache table. Once an
> entry is placed in the ARP cache, it is allowed to remain
> there until its lifetime expires or until its table entry is reused because
> it is the oldest entry.
>
> ArpCacheSize REG_DWORD Number Default: 62
>
> Determines the maximum number of entries that the ARP cache table can hold.
> The ARP cache is allowed to grow dynamically until
> this size is reached. After the table reaches this size, new entries can
> only be added by replacing the oldest entries that exist.
>
> DatabasePath REG_EXPAND_SZ Pathname Default:
> %SystemRoot%\system32\drivers\etc
>
> Determines where TCP/IP and NBT look for the hosts, services, networks,
> protocols, NETRC, and LMHOSTS files.
>
> IpEnableRouter REG_DWORD 0 or 1 Default: 0 (false)
>
> Determines whether IP routing is enabled between local interfaces. IP
> routing is always enabled for packets generated by the local
> host. This parameter determines whether, for packets received on an
> interface and not destined for this host, IP will attempt to actively
> forward the packets to hosts that can be reached via its other interfaces.
>
> IpReassemblyTimeout REG_DWORD Number of seconds Default: 60 seconds
>
> Determines how long IP accepts fragments when attempting to reassemble a
> previously fragmented packet. That is, if a packet is
> fragmented, all of the fragments must make it to the destination within this
> time limit; otherwise, the fragments will be discarded and
> the packet will be lost.
>
> TcpDisableReceiveChecksum REG_DWORD 0 or 1 Default: 0 (false, that is,
> checksums will be checked on receives)
>
> Specifies whether Checksums is disabled on receive.
>
>
> TcpDisableSendChecksum REG_DWORD 0 or 1
>
> Default: 0 (false, that is, checksums will be generated on sends)
>
> Specifies whether Checksums is disabled on send.
>
>
> TcpKeepCnt REG_DWORD Number in Minutes
>
> Default: 120
>
>
> Specifies how often TCP/IP will generate keep-alive traffic. When TCP/IP
> determines that no activity has occurred on the connection
> within the specified time, it generates keep-alive traffic to probe the
> connection. After trying TcpKeepTries number of times to deliver
> the keep-alive traffic without success, it marks the connection as down.
>
> TcpKeepTries REG_DWORD Number Default: 20
>
> Specifies the maximum number of times that TCP/IP will attempt to deliver
> keep-alive traffic before marking a connection as down.
>
> TcpLogLevel REG_DWORD Number Default: 16 (log everything)
>
> Specifies how verbose TCP/IP should be about logging events in the event
> log. The highest level of verbosity is 16, and 1 is the
> lowest level. The following shows general information about these levels.
>
> Level Events to be included
> ---------------------------------------------
> 1 Only the most critical errors
> 4 Serious protocol violations
> 8 Nonserious protocol violations
> 12 Information about unusual events
> 16 Information about unusual events that
> some networks normally allow
>
>
> TcpMaxConnectAttempts REG_DWORD Number
>
> Default: 3
>
>
> Specifies the maximum number of times TCP/IP attempts to establish a
> connection before reporting failure. The initial delay between
> connection attempts is 3 seconds. This delay is doubled after each attempt.
>
> TcpMaxRetransmissionAttempts REG_DWORD Number Default: 7
>
> Specifies the maximum number of times that TCP/IP attempts to retransmit a
> piece of data on an established connection before ending
> the connection. The initial delay before retransmitting is based on the
> current estimate TCP/IP makes of the round-trip time on the
> connection. This delay is doubled after each retransmission. Acknowledgment
> of the data results in a recalculation of the estimate for
> the round-trip time.
>
> TcpNumConnections REG_DWORD Number Default: 64
>
> Specifies the maximum number of TCP endpoints.
>
>
> TcpRecvSegmentSize REG_DWORD Bytes
>
> Default: 1460
>
>
> Specifies the maximum receive segment size.
>
>
> TcpSendDownMax REG_DWORD Number
>
> Default: 16384
>
>
> Specifies the maximum number of bytes queued by TCP/IP.
>
>
> TcpSendSegmentSize REG_DWORD Bytes
>
> Default: 1460
>
>
> Specifies the maximum send segment size.
>
>
> TcpWindowSize REG_DWORD Number
>
> Default: 8192
>
>
> Sets the size of the TCP send and receive windows, which is the amount of
> data that can be accepted in a single transaction. This
> parameter is important in transferring files between a client and a server
> and is critical for performance for one-way traffic, such as for
> FTP.
>
> UdpDisableReceiveChecksum REG_DWORD 0 or 1 Default: 0 (false--that is,
> checksums will be checked on receives)
>
> Specifies whether Checksums is disabled on receive.
>
>
> UdpDisableSendChecksum REG_DWORD 0 or 1
>
> Default: 0 (false--that is, checksums will be generated on sends)
>
> Specifies whether Checksums is disabled on send.
>
>
> UdpNumConnections REG_DWORD Number
>
> Default: 64
>
>
> Specifies the maximum number of UDP endpoints.
>
>
> ADAPTER CARD PARAMETERS FOR TCP/IP
>
> These parameters for TCP/IP are specific to individual network adapter
> cards. These appear under the following Registry path, where
> adapter name# refers to the Services subkey for the specific adapter card:
>
> HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
> \adapter name#\Parameters\Tcpip
>
>
> BroadcastType REG_DWORD 0 or 1
>
> Default: 1 (all 1 s)
>
>
> Determines whether broadcast packets contain all 0 s or all 1 s as the
> broadcast address. The most common broadcast type is all 1 s.
> The all-0 s setting is provided for compatibility with BSD 4.2 systems.
>
> ForwardBroadcasts REG_DWORD 0 or 1 Default: 0 (false)
>
> Specifies whether broadcasts should be forwarded between adapters. If
> enabled, broadcasts seen by this interface are forwarded to
> other IP interfaces.
>
> KeepAlive REG_DWORD 0 or 1 Default: 1 (true)
>
> Determines whether TCP connections that request keep-alive packets result in
> keep-alive packets being sent. This feature is used to
> determine when inactive connections can be disconnected. When a connection
> becomes inactive, keep-alive packets are periodically
> exchanged. When 20 (the default value for TCPKeepTries) consecutive
> keep-alive packets go unanswered, the connection is broken.
> This disconnect is initiated by the endpoint that is sending keep-alive
> packets.
>
> MTU REG_DWORD Number in octets Default: 0 (That is, use the value supplied
> by the adapter.)
>
> Specifies the maximum transmission unit size of an interface. Each interface
> used by TCP/IP may have a different MTU value specified.
> The MTU is usually determined through negotiation with the lower driver,
> using that lower driver s value. However, that value may be
> overridden.
>
> Ideally, the MTU should be large enough to hold any datagram in one frame.
> The limiting factor is usually the technology making the
> transfer. Some technologies limit the maximum size to as little as 128;
> Ethernet limits transfers to 1500; and proNet-10 allows as many as
> 2044 octets per frame.
>
> Datagrams larger than the MTU value are automatically divided into smaller
> pieces called fragments; size is a multiple of eight octets.
> Fragmentation usually occurs somewhere through which the traffic must pass
> whose MTU is smaller than the encapsulated datagram.
> If fragmentation occurs, the fragments travel separately to the destination
> computer, where they are automatically reassembled before
> the datagram is processed.
>
> RouterMTU REG_DWORD Number in octets Default: 0 (That is, use the value
> supplied by the lower interface.)
>
> Specifies the maximum transmission unit size that should be used when the
> destination IP address is on a different subnet. Each
> interface used by TCP/IP may have a different RouterMTU value specified. In
> many implementations, the value of RouterMTU is set
> to 576 octets. This is the minimum size that must be supported by any IP
> node. Because modern routers can usually handle MTUs
> larger than 576 octets, the default value for this parameter is the same
> value as that used by MTU.
>
> Trailers REG_DWORD 0 or 1 Default: 0 (false)
>
> Specifies whether the trailer format is used. This feature provides
> compatibility with BSD 4.2 systems. When this feature is enabled,
> TCP/IP header information follows the data area of IP packets.
>
> Reference: "The Windows NT Resource Kit for Operating System Version 3.1"
>
> Additional reference words: prodnt 3.10
>
>
>
> KBCategory: kbother
> KBSubcategory: ntregistry
>
> THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
> PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS
> ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
> OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO
> EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
> ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
> CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
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> POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION
> OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
> SO THE FOREGOING LIMITATION MAY NOT APPLY.
>
> Copyright Microsoft Corporation 1996.
>
>
>
>
>
