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TCP-group 1995

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Re: ETHRAX25 - Where is it?

>>I have release notes from a program called ETHRAX25.
>I did find it.
>Has anyone used it?

Yes.  And it does work!  Gary Grebus, K8LT (balrog!glg@mv.mv.com) wrote a
psuedo ethernet to encapsulated KISS driver that will make a KISS TNC
connected to a COM port look like an ethernet driver.  I successfully used
it in MS Windows with Trumpet Winsock and Mosaic.  You can do the Web on Packet!

Here's a quick howto:

Load ethrax25.com and winpkt.com in DOS via the winload.bat file that comes
with the ethrax25 zip file.  Load up MS Windows.  Setup and run Trumpet
Winsock to talk to the ethrax25 driver.  Now that Trumpet is up and running
you can use any winsock compliant program.  I successfully used Mosaic (ver.
2.0a2, the last 16 bit version), WINQVT for FTP and TELNET, and the Trumpet
Apps (telnet and ftp).  I could not get Netscape to work and I suspect that
not all winsock programs will.

You're not limited to Trumpet Winsock, Steve N5OWK used SuperTCP.  I include
a post he did last summer on the subject.

Ethrax25 conjures up some ideas, like writing packet radio apps that are
winsock compliant and take advantage of the packet radio environment rather
than using land line based applications.

I've included the ETHRAX25 Readme below.

Steve, N7HPR


From: ssampson@sabea-oc.af.mil (Steve Sampson)
Subject: AX.25 Packet Driver
To: tcp-group@UCSD.EDU
Date: Sun, 10 Jul 1994 08:18:56 -0500 (CDT)

Just a note to thank Gary Grebus for the well done packet driver for AX.25!
I plugged it in today and experimented with it using SuperTCP (Frontier
Technologies).  It works as advertised.  Now I only wish I had a better RF
path. . .

The problems I had getting started was:

        Don't try to use the interrupt that is shown in his axample with
SuperTCP (0x7E) as it likes 0x6b.  What I did was add the driver to the
installation floppy by deleting the SLIP8250 driver and modifying the
packet.inf file (I commented out the check= parameter as the calculation of
this number is unknown by me).  This makes it easier to just click on packet
driver on installation, and it will offer ethrax25 as an option.  I found at
this point it liked to use 0x6b.  I also found it liked to turn on hardware
flow and SLIP, so after installation I modify the autoexec.bat to delete the
SLIP part, but it seems to work OK using hardware flow (-h).  You have to go
through the servers and make sure those things that are specified in seconds
are adjusted for your network.


        I notice that the MTU of the driver is set for 1514 (GIANT).  I wonder
if this should probably be 236 (256 - 20)?  Better would be an ax25conf.exe
parameter probably, as this could be increased on higher speeds.

It looks like a lot of hard work by Gary, thanks again,
Steve, N5OWK


              ETHRAX25 - Ethernet to AX.25 Packet Driver
                           Revision: 940530
                             30 May 1994

ETHRAX25 is a modified version of the ETHERSL packet driver from the Crynwr
collection.  It provides an Ethernet (Class 1) interface to the application,
and produces AX.25 UI frames, encapsulated in KISS on a serial port.

Outgoing Ethernet frames are converted into AX.25 Unnumbered Information
(UI) frames.  The application sees pseudo-Ethernet addresses which are an
encoded representation of the AX.25 address.  The AX.25 frame is then
encapsulated in KISS framing and sent on the specified serial port to a
KISS-mode TNC.

The reverse is done for incoming KISS frames, which are converted to
pseudo-Ethernet frames for the application.

If the frame contains an ARP packet, the driver translates the hardware
addresses between AX.25 address and pseudo-Ethernet addresses as needed.
Thus ARP works transparently.  The Ethernet broadcast address
ff-ff-ff-ff-ff-ff is converted to the AX.25 broadcast address QST-0 and vice


The driver is loaded in the same fashion as other packet drivers.
The parameters are:

ETHRAX25 <packet_int_no>  [-h] [hardware_irq] [io_addr] [baud_rate]
        [send_buf_size] [recv_buf_size]

-h enables hardware handshaking on the serial port.

Since the application believes it is talking to an Ethernet, there are some
AX.25 and TNC parameters which must be set before the application is
started.  These are set using the AX25CONF utility:

AX25CONF <packet_int_no> [-stat] [-mycall <ax25 addr>]
                         [-txdelay n] [-persist n] [-slottime n] [-txtail n]

        <packet_int_no>  -- the interrupt number for the packet driver
        -stat            -- reports driver statistics
        -mycall ax25addr -- sets the AX.25 address (callsign with
                            optional SSID)
        -txdelay n       -- sets the TNC's txdelay (10 msec units)
        -persist n       -- sets the TNC's p-persistence
        -slottime n      -- sets the TNC's slottime (10 msec units)
        -txtail n        -- sets the TNC's txtail (10 msec units)

If the driver is being used with a MS Windows application, remember to load
the WINPKT driver after loading ETHRAX25.


The current version of the driver has been tested with a small set of DOS
and Windows applications.

Under DOS, the driver has been tested with WATTCP (7/16/93 vintage) and
Kermit 3.13 at 9600 baud.  However, since both of these IP stacks are tuned
for Ethernet or fast serial links, they are not useable over 1200 baud radio
links.  The driver was tested by connecting the serial line to a system
running KA9Q NOS, which was configured as if connected to a KISS TNC.  Ping,
telnet, ftp, and DNS seem to work.

Under Windows, the driver has been tested with the Trumpet Winsock TCP
stack, Version 1.0 A.  The overhead introduced by Windows causes packets to
be dropped when running the serial line at 9600 baud.  This can probably be
fixed by using a serial port with a 16550 UART.  The line works reliably at
2400 baud.

The driver was tested running the Trumpet newsreader, the ping, hopcheck,
telnet, and ftp utilities that come with Trumpet Winsock, and WS_FTP.  All
of these "worked" over a 1200 baud radio link.  I put "worked" in quotes
because, while there don't appear any driver-related problems, Trumpet
Winsock TCP stack appears to have some quirks which surface when running
over something that slow.

The WS_PING utility (931003) always gets a fatal error, but that sometimes
happens when running over Ethernet as well.

Other protocols which pass hardware addresses (like BOOTP) probably won't
work without explicit support in the driver.

The assembler code was assembled with Borland TASM 2.0.  Thee C code was
compiled with Borland C++ V2.0.


Steve, N7HPR

Naval Postgraduate School,  Monterey, CA 93943

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