1. History of DOS networking
  • "PC centric" approach Novell Netware, LAN Manager
  • "UNIX centric" approach PC-IP, PC/TCP, Packet Drivers
  • Software by universities and hobbyists KA9Q, NCSA Telnet, CUTCP, Others
  • Proprietary software Picking up the pieces

    2. DOS networking today

  • Drivers | Protocols | Applications
  • Novell "NetWare DOS" and "TCP/IP Client" | Microsoft "LAN Manager Client" and "MS Client 3.0" | TCP/IP applications

    3. Practical Guide: Adding TCP/IP to DOS

  • Packet drivers | Installing a packet driver | ODI drivers | Configuration of NET.CFG | Explanation of the parameters
  • Installing ODI drivers | Alternative 1: ODIPKT | Alternative 2: PKT2ODI
  • NDIS drivers | Configuration of NDIS drivers | Explanation of the parameters
  • TCP/IP Kernel (Stack) | WatTCP / Watt-32 | Usage
  • TCPDRV / NTCPDRV | Usage | Other TCP/IP Kernels Download also as PDF.

    This document describes how to network a computer using DOS. System used for testing is FreeDOS. Most things are supposed to work with other versions of DOS as well. How to add TCP/IP capabilities to a DOS machine is a detailed guide through the installation and configuration of drivers and other required software.

    All solutions described in this document were tested on a Compaq Contura Aero 486SX33 laptop with 20 MB RAM.

    Tried the following network interface cards (NIC), all PCMCIA:

  • 3Com Megahertz 3C574 10/100 LAN PC Card,
  • 3Com EtherLink III 3C589 10Mbit Card
  • D-Link DFE-670TXD Fast Ethernet PC Card.
    Cards are configured by SystemSofts CardSoft Software, which is available for the specified laptop as Compaq softpack SP1045.EXE. It also can be downloaded from driverguide as "SystemSoft Version 3.1, CARDSOFT.ZIP".

    Network is 100Base-T Ethernet LAN connected to the internet through a DSL router. FreeDOS version is 1.0.

    Parts of document inspired by Michael Bernardi's "DOS Networking HOWTO". Links there and FAQs and applications were of great value. Screenshot of "LAN Manager 2.1" in chapter LAN Manager was taken by Michal Necasek for his "History of OS/2" with permission to use this screenshot. Photo of software package "Workgroup Add-On for MS-DOS" in the same chapter by Dirk Makowski for his "Winhistory", a huge collection of items and screenshots of historic software.

    Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.

    1. History of DOS networking

    More about the history of TCP/IP networking with DOS in Steven Baker's "Net Worth - Desktop TCP/IP At Middle Age". This left a time frame for others. Two approaches for DOS networking, described as "PC centric" and "UNIX centric".

  • "PC centric" is a way to network a group of PCs to share files and resources (f.i. printers).
  • "UNIX centric" is to develop DOS versions of standard UNIX network programs and use them to access or provide UNIX-like services in LAN or internet (which, in the end, came down to file and resource sharing as well).

    "PC centric" approach

    Novell Netware

    In 1985 Novell, a former hardware manufacture of CP/M systems, released its product "NetWare 86" (v 1.5) for the PC. A version for the AT followed with "NetWare 286" (v 2.0) in 1986. Novell networked computers according to the client/server model: Clients running MS DOS and some memory resident (TSR) Novell software were able to "log in" to a server that ran "Novell NetWare Server". Once connected they could "map" a volume on the server to a driveletter in DOS and then use it like a local drive. NetWare also enabled the clients to use printers connected to the server. Client and server communicated over Novell's "Internet Packet Exchange / Sequenced Packet Exchange" (IPX/SPX) protocol. The driver architecture was called "Open Datalink Interface" (ODI). NetWare established a dominant position in the market until the middle of the nineties.

    LAN Manager
    Microsoft tried to break Novell's dominance by its own networking software for DOS. "Microsoft LAN Manager" 1.0 was released in 1987. It's networking software came with an own network driver model called "Network Driver Interface Specification" (NDIS). Just like Novell NetWare Microsoft's LAN Manager implemented a client/server architecture:
  • Server ran OS/2 as operating system and LAN Manager as server software.
  • Client ran DOS, OS/2 or Macintosh as OS and used a client software like "LAN Manager client" or "MS Client" for the connection to the server.

    With the "Server Message Block" (SMB) protocol merged into LAN Manager since 1991, Microsoft networks became able to do peer-to-peer networking as well. This was used by Windows for Workgroups 3.11, released in 1993. The mechanism is known to Windows users as "Windows share", "network neighbourhood" or "Workgroup". Workgroup Add-On for MS-DOS

    In October 1993 Microsoft released a tool called "Microsoft Workgroup Add-On for DOS" which allowed to have the same peer-to-peer networking possibilities in DOS. While the tool itself is not sold any longer, most of its functionally is still available by usage of "MS Client" and a special update called "WG1049" (see MS Client section).

    "UNIX centric" approach

    A small TCP/IP implementation that was linked into a few applications like finger, whois and netwatch. PC-IP was released with its source into the public domain. Drew Perkins from Carnegie Mellon University (CMU) and Dan Lanciani from Harvard University improved the code further. PC-IP still can be found in the web.
    The success of PC-IP inspired Romkey and friends to take the CMU version of the code and develop it into a proprietary product: "PC/TCP", which they sold through their company "FTP Software, Inc.", founded in 1986. The name was chosen after the popular 'File Transfer Protocol': PC/TCP included one of the first applications for FTP services on the PC.
    Packet Drivers
    Along with PC/TCP, FTP Software Inc. developed the "Packet Driver Specification", the first multiprotocol driver specification for PC network interface cards. On 12 Dec 1988 this specification was released as an open standard, for anyone to implement. Packet drivers proved useful to hardware vendors and software developers alike. Most of the public-domain or shareware TCP/IP applications have been written to interface with packet drivers only.

    Many packet drivers were written or managed by Russ Nelson at Clarkson University, who became known as the "Packet Driver King" - a story, he describes at his website. Nelson still distributes these drivers as free software through the site of his company "Crynwr" (which was named after the welsh word for "Quaker", his religious belief).

    One cause for the success of FTP Software's PC/TCP was this open packet driver interface, which made it easy to develop drivers and applications. When other driver interfaces like ODI and NDIS appeared on the scene, PC/TCP included converters: With a tool called ODIPKT.COM ODI drivers became usable as packet drivers, a tool called DIS_PKT.GUP did the same for NDIS drivers.

    PC/TCP also came with an external TCP/IP kernel called ETHDRV.EXE that allowed other programmers to call network functions within their applications without programming them themselves. All these features and an application suite that allowed DOS computers to access or provide TCP/IP services such as news, e-mail, ftp, telnet or network storage (PC/TCP even included a NFS client called InterDrive) made FTP Software Inc. market leader for DOS TCP/IP software.

    Software by universities and hobbyists

    PC-IP and its successor PC/TCP may have been the first or most successful TCP/IP kernels for DOS but they were not the only ones.

    Second after the early PC-IP kernel was the "
    "KA9Q Network Operating System" (NOS)" by Phil Karn in 1985. Karn, an engineer from Baltimore, Maryland had created it for CP/M two years before and then ported it to DOS. It also was one of the first TCP/IP applications for DOS that used FTP Software's packet driver specification. KA9Q simultaneously acted as an Internet client, a server and an IP packet router. The program was specialized for amateur packet radio, but also could be used f.i. as ftp- or webserver. KA9Q attracted many contributors. As Karn describes: "It was the Linux of its day".

    In 2002 KA9Q became free software (GNU GPL). Its descendants, JNOS and EZ-NOS (see also here and here) are still actively maintained.

    NCSA Telnet
    Based on the Packet Driver Specification several universities wrote TCP/IP applications and utilities for DOS PCs. In 1986 the "National Center for Supercomputing Applications" (NCSA) at the University of lllinois released "Telnet" - a client for UNIX telnet services which could act as FTP and rcp server as well. It was accompanied by TCP/IP tools like finger, whois and lpr. NCSA Telnet came with its own TCP/IP kernel, which was already built-in into the applications. The software was developed until 1995 (v2.308) and released with source into the public domain.
    Clarkson University in Potsdam, New York took version 2.2 of NCSA Telnet and modified it. They called their version CUTE or CUTCP. Eventually Rutgers University, New Jersey took over the maintenance and published the latest release in July 1993. In difference to NCSA Telnet, CUTCP supported the IBM-3270 emulation and was technically improved. It also became public domain.
    Minuet Version 1.0 Beta 18A
    Other developments at universities that should be mentioned are "Kermit", a terminal emulation for DOS written at the Columbia University, New York and the University of Minnesota's "Minnesota InterNet Users Essential Tool" ("Minuet"), a packet driver based suite of TCP/IP applications. Minuet provided a mouse driven graphical interface that integrated client applications as E-mail, Gopher, telnet, Usenet News, a web browser and FTP.

    Minuet is a good example for the unfortunate design of DOS software licenses in this era. In difference to the GNU General Public License (GPL) that became a standard in the GNU/Linux world, licenses for DOS software written at Universities and by hobbyists were mostly homebrewed. The Minuet license f. i. allowed free usage for the University of Minnesota faculty, staff and students. All others were expected to pay 50$ after 15 days evaluation. Distribution was allowed for non-commercial reasons only.

    Proprietary software

    Beneath FTP Software Inc.'s PC/TCP a lot of other commercial applications could be found on the market for DOS TCP/IP networking software ten or fifteen years ago. Up to 30 TCP/IP packages for DOS were available in the middle of the nineties, including IBM "TCP/IP for DOS", NetManage "Chameleon", Sun "PC-NFS", Novell "LAN WorkPlace", Frontier Technologies "SuperTCP" or Artisoft "Lantastic". A comparison of their features can be found here. Read also the corresponding article in the "Network Computing" magazine.
    Picking up the pieces
    Some Novell and Microsoft tools can still be legally downloaded and used. And TCP/IP solutions by universities and hobbyists that were released into the public domain, as shareware and even as postcardware, are still around.

    A few projects are still alive: The graphical DOS browser Arachne is actively developed again by a group of programmers after it was released under the GNU GPL. Also ssh2dos, Watt-32 and the KA9Q successors EZ-NOS2 and JNOS2 are still maintained and developed. Even new DOS TCP/IP software has been written recently, although there seems to be some reluctance to release the source and give these creations a future as free software projects.

    2. DOS networking today

    Here we learn about network drivers, protocols and applications for a DOS PC. For more information try Eugene Blanchard's "Introduction to Data Communications" More recent version here).
    Ethernet is today's dominant network hardware technology. For such network adapters three types of driver can be used.
  • Packet drivers, invented by FTP Software Inc.
  • Open Datalink Interface (ODI) drivers, developed by Novell and Apple
  • Network Driver Interface Specification (NDIS) drivers, developed by Microsoft and 3Com.

    All are multiprotocol network drivers, meaning they are able to support multiple protocols over the same card. Earlier drivers did support only a single protocol. Multiprotocol drivers communicate directly with the network interface card and provide a published interface specification, to which applications can be written. Good general introduction "Implementing Multi-Protocol Network Drivers in a DOS Environment" by the University of Georgia, Athens, Georgia (U.S.).

    The following protocols are supported by these three drivers:

    TCP/IP has become the default protocol for Local Area Networks (LAN).
    NetBEUI was the default protocol for LANs in Microsoft systems until Windows 2000. Replaced by NetBIOS over TCP/IP (NBT) and then by TCP/IP. The application level network protocol SMB for instance can run directly atop of TCP since Windows XP.
    Novell's IPX was used in NetWare, which was the default networking solution for personal computers running DOS or Windows 3.x. Since 1998 NetWare is able to run on TCP/IP, more recent versions use it per default.

    Three ways of networking used with DOS.

    While the above categories should cover most programs, there are a few exceptions. One of them is "Invisible LAN", a NetWare-like DOS application that even comes with an own protocol called "TransBIOS". Another special type of applications are network bootdisks, which are able to work with a broad range of hardware and use multiple protocols. Bootdisks are mostly used for backup, restore and repair. They can be extremely helpful.
    Examples are: Bart's Network Boot Disk | Drivesnapshot | Netbootdisk

    Novell "NetWare DOS" and "TCP/IP Client"

    Novell provides software for free:

    On the sites above Novell includes a warning that this software is neither maintained nor supported any longer. Useful information about Novell's DOS clients can still be found at the newsgroup "novell.support.os.client.dos-win3x" which was active until 2004. More recent information and useful links about using NetWare with DOS can be found at "DOS Solutions".

    Microsoft "LAN Manager Client" and "MS Client 3.0"

    Download from Microsoft's ftp-site and are free for "internal use", but not for distribution. Excellent review, installation report and comparison of both Microsoft products by Dutch programmer Jacco de Leeuw. Ken from British website "DOS Solutions" gives a detailed overview over many resources related to MS Client . U.S. programmer Jonathan Young has created a nice looking MS Client installation walkthrough with many screenshots. James Hatridge wrote a nice article about MS Client for Linux Journal in 2002. Installation guides in German language have been written by Volker Rüddigkeit, by Gerhard Zeiser, by Gerd Röthig, by Michael Vogl and by Stefan Mayrhofer.

    Popularity of the thirteen year old MS Client 3.0 may be caused by the possibility (but not officially supported) to use an update called "WG1049.EXE" to add server functionality to the client. This adds features comparable to those of the "Workgroup Add-On for DOS", no longer sold by Microsoft.

    This "hack" seems to give people hope to be able to integrate their DOS machine into a modern Windows XP or GNU/Linux SMB Workgroup. There may be limits, though.

    Steven Baker critically remarks, that, while the core TCP/IP protocol remained stable over the years, Microsoft's SMB protocols changed from upgrade to upgrade and exist "in a dozen different dialects". So compatibility is an issue. Other problems can be caused by the authentication methods that are used with Windows or Samba. Some files from the "MS Client" package are essential for use of TCP/IP applications over today's common NDIS drivers.

    TCP/IP applications

    DOS TCP/IP applications include classic networking tools as ping, lpr or finger as well as SSH and NFS clients, FTP servers, webservers, mail and news software or web browsers. There is even a complete peer-to-peer networking solution called "Network Enhanced Operating System" (NeOS) which was developed 1995-2000 as part of European Union's "EUREKA" project. Now it is postcardware.

    Michael Bernardi has collected a list of more than hundred TCP/IP applications available for DOS. There also other lists here, here and here, which may contain additional information. A recent and constantly updated resource for DOS networking applications is the British "DOS Solutions". Links to other DOS resources are collected in FreeDOS technote 157. I also found the nostalgia site oldskool.org pretty helpful. Information can still retrieved from usenet newsgroup comp.protocols.tcp-ip.ibmpc, especially from their FAQ, which is posted in parts one, two and three.

    "Arachne" is a graphical web browser for DOS. It was created in 1996 by Czech programmer Michael Polak and his company xChaos / Arachne Labs. In 2002 Michael Polak decided to make Arachne free software. The new license is the GNU GPL. It supports various picture formats. Tables and frames are shown correctly, it renders HTML 4 and CSS 1.0 and the latest version (1.90J3) even understands UTF-8. Other Arachne services include FTP, NNTP, IRC-Chat, RSS, POP3 and SMTP. Look here for a complete history of the software. Arachne is still actively developed - programmers are invited to join a mailing list. The latest version can be found at the site of Glenn McCorkle. Read more about it at Wikipedia.

    "EZ-NOS 2" is one of the descendants of Phil Karn's KA9Q. It is currently developed by DOS Solutions. The software suite includes a webserver, a FTP-server and a bootp server as well as an email client. As all KA9Q descendants EZ-NOS 2 is licensed with the GNU GPL. The source can be downloaded as ez_src.zip.

    "SSH2DOS" is a SSH, SFTP and SCP client for DOS. These services more and more replace the classic telnet- and FTP-services, which are regarded as less secure. (The screenshot shows a closed SSH session to my Debian server.) SSH2DOS was created by Hungarian developer Nagy Daniel in 2000 and can be downloaded at Sourceforge.net. It is released under the GNU GPL. It uses code of the PuTTY SSH client as well as the WatTCP kernel library.

    3. Practical Guide: Adding TCP/IP to DOS

    The majority of TCP/IP applications for DOS uses the packet driver interface. So to be able to run them, we need to install the appropriate drivers first. To install a generic packet driver is the simplest way. But it isn't always possible, as modern network cards often only come with ODI- and NDIS-drivers. Anyway: ODI- or NDIS-drivers can also be used as packet drivers through special converters ("shims").

    Packet drivers

    Packet drivers work as an interface between the hardware (the network interface card) and the TCP/IP kernel (which is also called "protocol stack"). One sort of TCP/IP kernels work as an external program that can be called and used by various network applications. Other TCP/IP kernels are already built into network applications, a web browser for instance or a ftp-client. We will learn more about these kernels a bit further in this document.

    As already mentioned, packet drivers are multiprotocol drivers so TCP/IP isn't the only kernel that can work atop of it. As you can see in the figure above, it is also possible to run Novell NetWare over of a packet driver: Specialized drivers like IPXPD.COM or PDIPX.COM support IPX over the packet driver interface. The NetBEUI protocol can't be used on top of a packet driver though, as the packet driver interface is too different from NDIS.

    The first place to look for a packet driver should be the installation medium that came with your card. Packet drivers often have the letters "PD" in their names, so the packet driver of a 3com 3C589 PC-Card is called "3C589PD.COM" and the driver of the D-Link DFE-670TXD PC-Card is called "DFE670PD.COM". Look for a directory "PKTDRV" on the CD or floppy that came with your card.

    For ISA and PCI network cards a packet driver may be found at Russell Nelson's Crynwr project - a resource of public domain packet drivers. PCMCIA drivers seem to be rare there, though.

    Georg Potthast provides a collection of PCI card packet drivers and a tool called NICSCAN.EXE to determine the chipset of PCI network cards. He found that packet drivers are often the same for many models by the same manufacturer; recommends finding a packet driver by chipset.

    Installing a packet driver

    To install a packet driver, add a line to AUTOEXEC.BAT (example for 3c589 PCMCIA card):
    LH 3C589PD.COM 0x60 5 0x300
    In the example above the driver is loaded into high memory by using the command "LH". The first option ("0x60") sets the software interrupt (vector) used by the driver. The most frequently used packet driver software interrupt number is 0x60. The second option ("5") sets the IRQ, the third option ("0x300") sets the I/O port. Some drivers only need the vector and find the other values by themselves. Most packet drivers can be unloaded after use with the option "-u".

    That's all. After successfully installing a packet driver, you can skip the next two steps (ODI / NDIS drivers) and proceed with the TCP/IP kernel.

    ODI drivers

    "Open Datalink Interface" (ODI) drivers were originally needed for Novell NetWare. But that doesn't mean they can not be used for packet-driver-based TCP/IP applications. In fact, they were used for this since they were invented. An ODI driver is a good choice, if you cannot get a packet driver. Look for a directory called "netware", "nwclient", "ODI" or "VLM" on the installation floppy or CD-ROM. The drivers are executables, their names look like "3C574.COM" or "DFE670.COM".

    In the language of the ODI specification these drivers of the network card are called "Multiple Link Interface Driver" (MLID). The MLID communicates directly with the hardware of the network interface card. The MLID receives packets for different protocol stacks (kernels) in the system and passes these packets to a second piece of software, the "Link Support Layer" (LSL). The LSL then determines which protocol stack is to receive the packet. Both, MLID and LSL form the ODI architecture.

    Need an additional file to get ODI working: The LSL, which is a file called "LSL.COM". This file is part of the "DOS NetWare Client", which can be downloaded at Novell. Novell's download site explicitly remarks "LICENSE: FREE" for it. After download and extraction, the file "LSL.COM" can be found in the folder "NIOS". To use ODI with packet driver based TCP/IP applications, need to download another software, a "Packet Driver to ODI Converter". Converters are also called "wrappers" or a "shim". We have three options.

    With the MLID, the LSL and the converter we have most of the files needed. The only one missing is the configuration file "NET.CFG". An example file with settings supposed for your card may be found on the CD or floppy that came with it and should be located in the same directory as the ODI driver.

    Configuration of NET.CFG

    Edit main configuration file NET.CFG. If it doesn't exist, create it. Choose a directory - default locations of NET.CFG seem to be C:\NWCLIENT or C:\NET. The location should be in same directory, where LSL.COM and driver is found. An example NET.CFG which came with the 3Com 3C574 PC Card shows a lot of configuration settings, that are needed for Novell NetWare and other software. For using packet driver based TCP/IP applications the following four lines in NET.CFG are enough:
    --- NET.CFG ---
    Link Support
      buffers 8 1600
    Link Driver 3C574
     Frame Ethernet_II
    Explanation of the parameters
    Line "Link Support" configures the LSL. Options are: "buffers", "max boards", "max stacks" and "mempool". We only need to set: buffers 8 1600

    Determines number and size of receive buffers of the LSL. Default communication number for TCP/IP is 8. Author of ODIPKT, Dan Lanciani recommends to use a buffer size of 1600 bytes for ODIPKT.

    Link Driver 3C574 configures the MLID (driver of network card). First, the name of driver is specified. Change to the name of your NIC. Configure the "frame" or "envelope type" (both declarations work and mean the same thing) used by this driver:

    Frame Ethernet_II
    It is possible to define more than one frame type here: We already heard that ODI is a multiprotocol driver, so the MLID is able to use more than one frame and protocol with the same hardware network board. For this purpose it defines logical boards for each defined frame. Possible frames are for instance "ETHERNET_II" (IP protocol), "ETHERNET_802.2" or "ETHERNET_802.3" (both IPX/SPX protocol).

    For the packet driver converter, that we want to start later, it is mandatory to define at least the Ethernet II frame here. You also have to inform ODIPKT in a command line parameter to use the board with the ETHERNET_II frame (see below).

    Full documentation of parameters in NET.CFG see "NetWare Client for DOS and MS Windows Technical Reference".

    Installing ODI drivers

    Once configured NET.CFG start ODI drivers in AUTOEXEC.BAT at boot. The first thing to start is Link Support Layer:

    Change paths for your system. The "/C" option tells LSL where to find NET.CFG. Only necessary, if NET.CFG is not in the same directory as LSL.COM.
    Now start MLID: LH C:\NETWORK\PCMCIA\3C574\ODI\3C574.COM

    Last install Packet Driver to ODI Converter. Choose between ODIPKT or PKT2ODI.

    Alternative 1: ODIPKT

    With free converter ODIPKT.COM by Dan Lanciani, start with a command in AUTOEXEC.BAT:

    First number of parameters above ("0") determines the board that uses ETHERNET_II frame. The following example assumes you defined different frames (also known as "envelope types") in NET.CFG:

    --- NET.CFG ---
    Link Driver 3C574
      FRAME ETHERNET_802.2
      FRAME ETHERNET_802.3
    Tell ODIPKT index number of logical board that supports the Ethernet II frame. Count the frames in NET.CFG: Ethernet II is the first one, the frame 802.2 is the second, the frame 802.3 is the third, snap is fourth.
    To make things a bit tricky, ODIPKT starts counting with "0" (like programmers do). According to example above:
    ODIPKT.COM 0 | board with ETHERNET_II
    ODIPKT.COM 1 | ETHERNET_802.2 (won't work)
    ODIPKT.COM 2 | ETHERNET_802.3 (won't work)
    ODIPKT.COM 3 | ETHERNET_SNAP (won't work)
    Only option that works for ODIPKT is the number that defines logical board with frame ETHERNET II, which is "0" in example.

    Second parameter ("96") for ODIPKT. This defines software interrupt (vector) used by driver. As learned configuring a packet driver, the most frequently used software interrupt number is 0x60, which is the hexadecimal value 60 (the "0x" is hex format). ODIPKT does not understand hex values; translate this parameter to a decimal number - which is 96.

    To use other values may try a hex-dec calculator or see the following list:

    0x60 = 96
    0x61 = 97
    0x62 = 98
    0x69 = 105
    0x6A = 106
    0x7D = 125
    0x7E = 126
    Packet driver is installed. Use command "ping" from the WATTCP package to test.

    Alternative 2: PKT2ODI

    An alternative is Caldera's PKT2ODI.EXE as Packet Driver to ODI Converter. PKT2ODI.EXE will be started in AUTOEXEC.BAT with command: LH C:\NETWORK\NWCLIENT\PKT2ODI.EXE /B:1 /I:69

    The "/B" option tells PKT2ODI which logical board to use. As previously choose board that uses the Ethernet II frame. Different to ODIPKT, PKT2ODI starts counting with "1", so if NET.CFG appears:

    --- NET.CFG ---
    Link Driver 3C574
      FRAME ETHERNET_802.2
      FRAME ETHERNET_802.3
    use parameter: PKT2ODI.EXE /B:1
    Define use of first board (the one with ETHERNET_II). Remember to use the board with Ethernet II, otherwise converter cannot communicate with driver and complain of finding MLID. Second parameter, "/I" sets the software interrupt (vector) used by driver. Should be 0x60 but won't work with PKT2ODI. Program doesn't accept interrupt vectors 0x60 to 0x68.
    Use vector 0x69: PKT2ODI.EXE /I:69

    Unusual interrupt vector like 0x69 can be a problem for some TCP/IP applications. Must be configured to use this vector. Some programs, like webserver SIOUX, may not function, if vector is not 0x60.

    Start LSL, MLID and converter, the packet driver interface should function. Proceed with chapter "TCP/IP kernel".

    NDIS drivers

    Drivers based on the "Network Driver Interface Specification" (NDIS) are the default in the Windows and OS/2 world. Most recent version is NDIS 6 used in Windows Vista. Windows 98 used NDIS 5, Windows 95 came with NDIS 3.1. In DOS use real-mode driver NDIS2. Probably a NDIS driver exists for your network card. Look for directory "NDIS2" in card installation files. Cannot find a driver, look at this site. The ending of the driver name has to be *.DOS, so for instance driver of 3com 3C574 PC-Card is "EL3C574.DOS". In the language of the NDIS architecture these are named "Media Access Control" (MAC) drivers.

    The MAC driver is only one component of NDIS architecture. Check NDIS 2.1 documentation Procedure:

    Configuration of NDIS under DOS has changed over time with different versions of the package. Some hints about the differences can be found here. In this document, we use NDIS files from MS Client 3.0. To use the NDIS2 (MAC) driver need more files. These are:

  • The Protocol Manager ("PROTMAN.DOS" and "PROTMAN.EXE")
  • The bind utility ("NETBIND.COM")

    These are part of MS Client 3.0 downloaded here: ftp://ftp.microsoft.com/bussys/Clients/MSCLIENT/DSK3-1.EXE

    Three files are part of "DSK3-1.EXE". Use utility "EXPAND.EXE" included on the first disk to decompress.

    NETBIND.COM is already uncompressed. Files are ready. Last item is "Packet Driver to NDIS Converter". Get the widely used "DIS_PKT9.DOS" (version 9) or alternatively the slightly newer (version 11) "DIS_PKT.DOS". There are no differences in usage and handling. Both written by Prof. Joe R. Doupnik (Utah State University) and Dan Lanciani (Harvard University).

    Configuration of NDIS drivers

    This is a minimal installation of MS Client 3.0. The only purpose is to use a packet-driver application. For this purpose:
    Copy the four files
    into a directory, for instance C:\NET. Copy the MAC driver of network interface card, for instance: EL3C574.DOS into this directory. Create configuration file needed for NDIS architecture: Create a file with the name PROTOCOL.INI inside the C:\NET directory. For our minimal configuration it needs the following lines:
    --- PROTOCOL.INI ---
    Explanation of the parameters
    Like other *.ini files, PROTOCOL.INI is structured into section names in square brackets and item names with values assigned.
    [protman] defines the Protocol Manager. loaded as driver PROTMAN.DOS named "PROTMAN$". Section and line are mandatory.
    [EL3C574] defines network interface card. By default the section itself is named after the card - this is useful, if you have more than one network card and use different sections for different cards. Section name is the first value to change. Good idea to name it after your network card. Could name section to "netcard", "NIC" or even "baked_beans" - as long as you also change all the other lines in PROTOCOL.INI that point to that section.

    The next line is "DriverName=EL3C574$" which defines driver for network interface card. In example is EL3C574.DOS, named "EL3C574$". Modify with your driver name. Find correct name of driver in a text file "PROTOCOL.INI" that should be included with NDIS driver files supplied with card.

    Possible to add more lines to this section, to define special settings for network card. Consult the "PROTOCOL.INI" supplied with NDIS driver for more information. In many cases the line with drivername should be enough.

    "[PKTDRV]" defines Packet Driver to NDIS Converter, "DIS_PKT.DOS" or "DIS_PKT9.DOS". Both are called by the name "PKTDRV$".
    Important that converter binds to driver of network card. Achieved by "bindings=EL3C574". Note this name includes no "$" letter - it refers to the name of the section that defines the driver, not to driver itself. If you named section "[baked_beans]" you would write "bindings=baked_beans" here ;-).

    "intvec" specifies software interrupt vector used by packet driver. Hexadecimal value 0x60 per default.

    "chainvec" defines an available software interrupt. It's function is still a mystery to me. According to packet driver inventor FTP, adding a chain vector interrupt may improve packet processing speed and reliability. Users saw "a 10-fold increase in performance". To avoid EMM386 errors, some recommend to set an interrupt that increases the vector by decimal 8. So if the intvec is 0x60 (that is decimal 96), then the chainvec should be decimal 104 (96+8) which is hexadecimal 0x68. This is also described by one of the authors of DIS_PKT.DOS, Dan Lanciani. Please write if you find out more.

    These are settings in PROTOCOL.INI needed for our purpose. Final hint: if you consider changing some of these values at boot, for instance by a DOS boot menu, could use Horst Schaeffer's freeware "Inifile" Load drivers at boot. Modify system files with the following lines:

    --- FDCONFIG.SYS (FreeDOS) ---
    --- or CONFIG.SYS (MS DOS/other DOS) ---
    "/I" parameter tells Protocol Manager the location of PROTOCOL.INI. Unneeded if both in same directory.
    --- AUTOEXEC.BAT ---
    Note that NETBIND.COM can not be loaded high and should just be executed from AUTOEXEC.BAT. If you try to load it like a driver, it will abort with the message "run-time error R6009 - not enough space for environment".
    Test with ping.

    TCP/IP Kernel (Stack)

    TCP/IP kernel is also called "stack" or "protocol stack", because it consists of two layers: IP and TCP. IP runs on top of the hardware driver and TCP on top of IP, providing an interface to network applications. Modern operating systems have their own TCP/IP kernel already built-in: Microsoft come with "Winsock" since Windows 95. In GNU/Linux TCP/IP stack is part of Linux kernel. For DOS different types of TCP/IP kernels are available. They can either work as external programs or already built into applications. Every TCP/IP kernel must be configured with general information about the network, as IP address, netmask, nameservers and gateway, or it must be told to get this information via a BOOTP or DHCP server. Examples for external TCP/IP kernels for DOS are the free Trumpet TCP kernel NTCPDRV.EXE, the TCP/IP kernel of Novell NetWare TCPIP.EXE, Microsoft MS Client's TCPTSR.EXE and FTP Software Inc.'s ETHDRV.EXE. Examples for TCP/IP kernels that are already built-in into DOS applications are WatTCP, which is f.i. already built-in the graphical web browser "Arachne", the KA9Q kernel which is part of that program, the NCSA Telnet kernel which is built into the applications included in this suite, the CUTCP kernel and the University of Minnesota stack, which is part of "Minuet". According to Jeffrey L. Hayes from the retrocomputing website http://www.oldskool.org more than half of the DOS networking applications available use the WatTCP kernel.

    First look at WatTCP and successor Watt-32. Then examine NTCPDRV, the only free external TCP/IP kernel available. Last brief look at other external TCP/IP kernels.

    WatTCP / Watt-32

    Waterloo TCP (WatTCP) was written 1990 - 1992 at the University of Waterloo in Ontario Canada. Author Erick Engelke, then a developer in the Faculty of Engineering, today the university's Manager of Networks and System Integration. The core TCP engine of WatTCP was based on Geoffrey H. Cooper's TinyTCP. WatTCP was originally released under a homebrewed public domain license - binary and source were free for use, distribution was allowed only for non-commercial reasons. In 2004 Erick Engelke copyrighted the libraries under the terms of the GNU LGPL. WatTCP can be found at Erick Engelke's homepage or as WAT1104.ZIP at various sites in the internet. While the software is free, the WatTCP Programmer's Reference issold as PDF for 55$. WatTCP was ported to 32-bit by Gisle Vanem at Bergen, Norway in 1999. The port is called Watt-32. It supports 32-bit protected-mode as well as 16-bit real-mode. It comes with uncompiled applications, compiled versions can be downloaded here. There is a developer forum which is still active. WatTCP and Watt-32 are not external TCP/IP kernels. Both are just sets of libraries designated to programmers - they can use these libraries to implement TCP/IP functions into their applications. The WatTCP package includes such applications with built-in WatTCP kernel like "ping", "finger", "whois" or "lpr".

    Some important DOS network applications use the WatTCP libraries like Arachne or ssh2dos. A list of these apps is available at "DOS Solutions".

    No download needed to use WatTCP / Watt-32 kernel. It is already in the applications. What is required is a configuration file, named "WATTCP.CFG" basically the same in both versions. Located in applications directory per default. General settings:
    --- WATTCP.CFG ---
    # These are example values:
    my_ip =
    netmask =
    nameserver =
    nameserver =
    nameserver =
    gateway =
    # Uncomment, if your receive your configuration via DHCP
    # my_ip = dhcp
    Additional settings may be needed. A deeper introduction into the use of WatTCP programs at Smashco.


    Trumpet TCP driver is an external TCP/IP kernel working as a TSR program running on top of a packet driver. TCPDRV was created in 1992 by Peter Tattam, a programmer in the Psychology department of the University of Tasmania at Hobart, Australia. According to a biography on his website, he developed the shareware "Trumpet Newsreader" short time before and wrote the TCP driver just because nothing else was openly available for Turbo Pascal. Development eventually lead to the popular Windows software "Trumpet Winsock", which Tattam sold through his own company "Trumpet International of Australia", founded in 1994.

    TCPDRV 2.01 was released as "experimental version". In 1993 a version 3.01 followed, which was called NTCPDRV. Improvements included a more efficient memory usage and bug fixes. Both versions and the textfile TCP201.SPE (the specification for programmers) were made publicly available from the Trumpet website: trumpet.com.au/dosapps Licensing issues are simple: "These DOS applications are provided free without support." Thanks to the popularity of the trumpet software, it can be downloaded from various mirrors. A commercial version of the TCP driver is available from Peter Tattams new company "Tattam Software Enterprises".

    Download NTCPDRV.ZIP and extract. For documentation, download the older version TCP201.ZIP as well, which also includes several applications. The TCP/IP kernel has to be configured with the settings of your network. Done either by commandline parameters or by setting DOS environment variables.
    Start NTCPDRV.EXE with command (one line):
    NTCPDRV -ip= -netmask= -gateway= -dns-host=

    or configure by setting environment variables: Add lines to AUTOEXEC.BAT or batchfile to be started before NTCPDRV.EXE.

    --- AUTOEXEC.BAT ---
    set ip=
    set netmask=
    set gateway=
    set dns=
    The kernel automatically searchs for a usable interrupt vector, may also use parameter "-vec=61" to specify vector 0x61 provided by packet driver. See documentation for more possibilities. Once Trumpet TCP/IP kernel operating able to run several TCP/IP applications (for instance Trumpet Newsreader, webservers Sioux or Webserv). Machine also reachable from the network, try a ping request.

    Other TCP/IP Kernels

    Other external TCP/IP kernels are still legally downloaded. From Novell and Microsoft may be of use. Comments to this site? Ideas? Suggestions? Please drop a note! Don't forget to add your email, if you wish a personal reply. The comments are sorted from date. Ulrich Hansen, 12.12.2007 modified by others 1.08.2008
    Further questions visit FreeDOS User mailing list. DosNetcomment Ulrich's homepage