Sysop Registry


Running TCP/IP under Windows 95 via AX.25

With the TCP/IP module all TCP/IP services available under Windows 95 can be done also via AX.25. You should have some basic ideas of TCP/IP and Windows 95. If so, the installation is quite simple.

Before you start with this module please be sure that FlexNet is installed and running ok. That is: you can do "normal" packet radio QSO's with your terminal program. The installation of the TCP/IP module is done completely under Windows 95 and resembles the installation of an ethernet adapter:

  1. Copy all files of the archive FLEXIP95.LZH to the FlexNet subdirectory.
  2. Go to: "Control Panel -> Network -> Add -> Adapter -> Have Disk"
  3. Instead of "A:" use the FlexNet directory e.g. "c:\pcflex". You will see an entry
    "FlexNet IP -> AX.25".
  4. Select this entry and choose "OK". Now you have a virtual "adapter" on which the TCP/IP protocol can be installed as described in the Microsoft documentation:
  5. Go to: "Control Panel -> Network-> Add -> protocols -> Microsoft -> TCP/IP"
    You can now configure TCP/IP; a binding to a client or server is not necessary. When you exit this menu you will be asked to reboot. After doing this your installation is complete.


If you bind TCP/IP to "Server for Microsoft Network" and you are not behind a Firewall, somebody might get access to all services exported by your computer. This is NOT a deficiency of FlexNet, it is a deficiency of Microsofts network protocols, which are not designed to be run over a publically accessible radio network!

Routes are beeing defined in the "FlexNet Control Center". This is a simple job if you "ping" the target before. Any unresolved address resolution will show up as an "unknown" entry in the routing list. Just double click the entry and complete it with the appropriate AX.25 path. Note that FlexNet will not broadcast ARP requests for unresolved destinations! Incoming routes (e.g. when you have been pinged by another station) are automatically learned and permanently stored. For the presence, the mode "Virtual Circuit with TCP Compression" works only with other FlexNet targets (and presumably only within pure FlexNet networks).

We do NOT encourage you to use the "Datagram" mode as it uses UI frames that have to pass the entire distance between two partners for a retry in case of a lossy link. If possible use the "Virtual Circuit" mode; this is also the default.

The control button "permanent" will be necessary only in a few situations. When active, it locks the route and mode for a given IP destination so the system cannot switch to another route even if that would be the better choice.

If you change your network node or FlexNet channel, the redefinition of your targets is easily done with drag&drop operations from the "AX.25 tree view" menu. You can move complete trees within this view by a single click, so be careful.

On the very first start you will be asked the callsign of the IP stack. The SSID no. 10 is commonly used. Of course you shouldn't choose an SSID that is normally in use for "plain" AX.25 connects.

Be careful with the "Default Route". All packets for unknown targets will be sent there. If you are close to an IP router you can use this one as the default. Don't choose stations that share a digipeater input with other users as your default route. This will double the traffic and is therefore strongly discouraged!

It is always a good idea to dispense from using the default route and add new routes via the "IP routes" window when needed.

To complete the installation you need to define a nameserver. This nameserver shouldn't be too far away to receive the results within a reasonable time. Alternatively you can manually define the relation of names to IP addresses. This is done in the "HOSTS" file that is located in the WINDOWS subdirectory; this will speed up DNS requests considerably.

This documentation should cover most questions related to AX.25 configuration. It is not intended to solve problems you may have with the operating system. The matter of choice for these problems is to read the system documentation and/or to use the hotlines Microsoft offers ($$$). As this project also addresses radio amateurs who are new to TCP/IP, we are preparing a more detailed documentation. Watch out for it later in these pages.

pages created by Gerald Schreiber, dl9fck, last updated: March 2001