Support for Internet Ethernet access within JNOS
Design objective
Enables a PC running JNOS to serve as a outbound gateway, receiving email traffic (locally generated emails, or
SMTP email from other PCs running IP over AX.25 on amateur radio frequencies) and send SMTP emails to other
email servers on the Internet. This assumes that the PC is a residential PC with connectivity to the Internet via a
cable modem or DSL (Digital Subscriber Line) broadband connection.
This design requires the PC to be running in native MS-DOS mode. MS-DOS V3.0 and above, Windows 95, 98
and ME support that. It cannot run in the DOS compatibility box mode of Windows 2000, XP, etc.
Assumptions about the PC
Use the same Ethernet adapter as your regular PC RJ45 8-pin modular jack.
Assumes the Ethernet adapter is compatible with DOS packet drivers. This example assumes the Intel
PRO/100 Ethernet adapter.
For this example, it assumes you have an ISP broadband connection.
For this example, it assumes youve been assigned AMPR.ORG IP address 44.100.200.250, assigned to a
1200 baud AX.25 VHF radio network.
For this example, it assumes you have a neighboring gateway station (one port facing the Internet with an IP
address of 44.99.1.2, and one port facing a 1200 baud AX.25 VHF network with AMPR.ORG IP address
44.100.200.1), and other 44.100.200.x AMPR.ORG stations are reachable via the 1200 baud AX.25 VHF
network.
Assumptions about Internet Access
A broadband ISP connection via cable modem or DSL
Internet Service Provider implements DHCP for assigning IP addresses to the subscriber.
You (the ISP subscriber) use a wired firewall or wireless access point which translates DHCP IP address on the
ISP side to a fixed internal LAN network of 192.168.1.XXX. Assumes you use a Linksys router. (Note that a
192.168.1.XXX address implies a Linksys device. Other equipment vendors use a 192.168.y.xxx subnet
addressing scheme, where y is from 2 to 254. Adjust the IP assignment in the examples accordingly.)
Select a static IP address for the Ethernet port on your PC in the 192.168.1 subnet, other than 192.168.100 to
192.168.1.150. These are the dynamic IP addresses that the Linksys router will hand out to PCs. The IP
address used in this example, facing the Internet, is 192.168.1.253.
Your wireless access point/router has a gateway port 192.168.1.1, where IP traffic is gatewayed from your local
home PC LAN through that IP address to get to the Internet. This is used when specifying JNOS Ethernet port
eth0 (in these examples) to gateway traffic to through to the Internet.
The ISP provides a dynamically assigned DNS (Domain Name Service) IP address.
IP Ports needed are:
o UDP 53 Domain Name Service
o TCP 25 SMTP (Simple Mail Transfer Protocol)
o TCP 3600
Convers (if convers link is used)
o TCP 3601
Convers (if convers xlink is used)
o TCP 20
o TCP 21
o TCP 23
Optional FTP data
Optional FTP command
Optional Telnet
Primers on Packet Drivers for MS-DOS
http://www.dendarii.co.uk/FAQs/dos-net.html
http://fd-doc.sourceforge.net/wiki/index.php?n=FdDocEn.DOSNetworking
http://lazybrowndog.net/freedos
http://www.crynwr.com/packet_driver.html
http://www.crynwr.com/drivers/
Interface Design
If needed, download and configure packet drivers into the PC configuration.
Software Downloads
http://www.crynwr.com
Select the Intel100Mbps packet driver downloads, and save file e100b11b.zip. Save
the file, unzip it, and extract the packet driver <>.
C:\CONFIG.SYS
Dos=umb,high
C:\AUTOEXEC.BAT
JNOS AUTOEXEC.NOS
AUTOEXEC.NOS File Entry
# INTERFACE DESCRIPTIONS
#=======================
ifconfig eth0 description "Ethernet to the Internet"
Comment
Comments in the AUTOEXEC.NOS file start
with the pound sign (#). The descriptions
show with the port names when someone
issues a P command
AUTOEXEC.NOS File Entry
attach packet 0x60 eth0 4096 1500 192.168.1.253 192.168.1.1
Comment
Define the Ethernet port eth0. It assumes
the packet driver is loaded as a TSR
(Terminate and Stay Resident) driver, with
the hardware IRQ, I/O address and software
IRQ (0x60) supplied in config.sys or
autoexec.bat.
The software interrupt for the Ethernet driver
is 0x60 (a common software interrupt
number). The maxqueue size is 4096. The
MTU (Message Transfer Unit) size is 1500
characters. The IP address of the port in this
example, facing the Internet, is
192.168.1.253. This IP address is a madeup address in the same subnet as your
wireless access point unit. It should be
unique within the subnet for your wireless
access point. The specified IP address
192.168.1.1 is by this interface to gateway to
the Internet.
convers interface eth0 on
Sets up a conference call interface on eth0.
convers host yourname
Sets up yourname as the hostname for this
conference system
AUTOEXEC.NOS File Entry
Comment
convers mycall yourcallsign
Sets up yourcallsign as an AX.25 callsign
that will immediately connect incoming
connections to the conference system.
convers t4 1800
Sets the idle conference timeout timer at
1800 seconds (30 minutes).
convers maxwait 1200
Specifies 1200 seconds as the upper limit for
the time this JNOS system will wait to
reestablish a disconnected convers link that
originated at this system.
convers setinfo yes
convers link 206.97.195.20
Specifies the IP address (ex: 206.97.195.20)
to link with and form a conference system.
route add 44.48.30.100/32 eth0
Example: Specifies the route to IP address
44.48.30.100 is through the Ethernet port
eth0.
route add 44.106.62.10/32 asy0
Example: Specifies the route to IP address
44.48.30.100 is through the port asy0.
route add 44.100.200/24 asy0
Example: Adds an IP route for all
44.100.200.x subnet hosts (the AMPR.ORG
hosts in the 44.100.200 subnet) through port
asy0.
AUTOEXEC.NOS File Entry
Comment
route add 44/8 eth0
Adds an IP route for all 44.x.x.x hosts
(AMPR.ORG) through port eth0.
route add default eth0
Defaults all other IP traffic through port eth0.
# Trace all configured interfaces
trace
eth0 0000
Turns off trace messages on port eth0.
trace
eth0 0111
Turns on trace messages (display ascii
characters, non-ascii characters display as
periods) on port eth0, for input and output
messages.
