The Internet Extender Users Manual
1) IBM/Compatible PC with a 286 or higher processor
2) 1MB of RAM
3) <1MB or hard drive space or 1 bootable floppy
4) MSDOS 5.0 or higher
5) VGA adapter
6) 14.4Kbps or higher modem (if you use a modem to connect to the Internet)
7) Network Interface Card + Packet Driver (2 if you don't use a modem)
8) PPP packet driver (EPPPD for DOS -freeware- recommended)
Running the Internet Extender from the Hard Disk:
Uncompress the Internet Extender Archive into a temporary directory
and run the SETUP.BAT script. The script will create an INET_EXT directory
on your hard drive and copy the necessary files to that directory depending
on how you answer the questions it asks. There are 2 main configurations of
1) You are using a modem to dial up your ISP to dynamically receive an IP
address and connection to the Internet. You then have an Ethernet Adapter
connected to your local area network with its own addressing scheme.
2) You are using an Ethernet Adapter to connect through a Cable Modem, T1,
etc and your IP address is statically assigned to you. You then also have
an Ethernet Adapter connected to your LAN with its own addressing scheme.
Note: If you are using DHCP on your LAN, you will need to exclude an address
and statically assign it to the Internet Extender Machine.
The SETUP.BAT file is not perfect so I would suggest checking the
configuration files that it creates before trying to run the program. There
are 2 main configuration files that the Internet Extender needs to run:
NAPT.INI and PPPD.CFG (for modems only). I will explain each file in detail
so that you will know exactly what information you will need to get before
running the program. All of the configuration files should reside in the
same directory as the Internet Extender executable.
Note: The program comes with about 10 packet drivers for Ethernet Adapters.
This in no way will cover every Adapter made, so if the packet driver
specific to your Adapter isn't included you will need to get it from
the Installation Disk that your Adapter came with, from the adapter
website, or ftp://ftp.crynwr.com
local_ip: You specify the IP address of the Ethernet Card connected to
your LAN. It must be static, the program does not use DHCP.
local_mask: You specify the Subnet Mask specific to your LAN.
remote_ip: You specify the IP address of the Ethernet Card connected
ultimately to the Internet.
**if using a modem, place a semicolon before remote_ip.
remote_mask: You specify the Subnet Mask specific to the ISP's addressing
**if using a modem, place a semicolon before remote_mask.
local_pdi: You specify the packet driver interrupt (pdi) of the Ethernet
Card connected to your local area network.
**must be between 0x60-0x80.
remote_pdi: You specify the packet driver interrupt (pdi) of the Ethernet
Card/Modem connected to the Internet.
**PPPD will grab the first available interrupt.
tcp_server: You specify the IP address:Port of any TCP servers that
reside on the LAN that you would like people on the Internet
to have access to. You can have as many as you wish, but
they must have there own line for each one. Place a
semicolon before tcp_server if you do not have any servers
you would like world access to.
udp_server: You specify the IP address:port of any UDP servers that
reside on the local area network. Works the same as the
local_gateway: You specify the IP address of the local gateway if one exists
that you want to include.
**place a semicolon before local_gateway if not specified.
remote_gateway: You specify the IP address of the remote gateway if it not
automatically assigned by the ISP.
**place a semicolon before remote_gateway if not specified.
PPPD.CFG **for use with a modem only**
connect "chat -e '' ATDT5551212 login: username word: password"
COM#: You specify which COM port your modem resides on.
57600: You specify the maximum speed at which your modem can connect
modem: You are using a modem to connect.
connect: It calls the chat tool to call and connect to the ISP to
receive the addressing information. You must specify the
phone number of the ISP by replacing 5551212 with your number
You must specify your username/password by replacing them
respectively with your own.
Note: For more information about the PPPD.CFG or any part of the PPP driver
configuration, view the readme.txt included with the Internet Extender
It was written by Antonio Lopez Molero and his readme.txt will give
you more insight as to the options that can be included.
The final thing that you must worry about is how to execute the program.
These are the final steps in running the program. At the DOS prompt:
**The name of the Ethernet Packet Driver, and an Interrupt**
ex. 3C5X9PD.COM 0x61
**The name of your PPP Packet Driver, and an Interrupt**
ex. For a second Ethernet Card 3C5X9PD.COM 0x60
ex. For a modem EPPPD.EXE (interrupt automatically set to first available)
NAPT.EXE **Runs the Internet Extender Program**
OR just run INET_EXT.BAT that SETUP created based on your answers.
The packet drivers must be loaded before the program is run or else the
program will not start. It will inform you which packet driver has not been
properly loaded beforehand.
Running the Internet Extender from Floppy:
Create a bootable floppy with your Operating System (DOS/Windows) then
unzip the program archive to your hard drive into any temporary directory.
Run SETUP.BAT from the hard disk and when it asks you where you want it
installed, specify the floppy drive. But remember that you need to make sure
that you have the packet driver for your specific Network Adapter on the disk
as well. The process is the same as running from the Hard Disk.
Configuring for Local Servers
The Internet Extender is also designed to support static mappings of
TCP and UDP servers. It allows for Servers on the Local Area Network with
invalid IP addresses to be accessible by the global Internet. To accomplish
this, you must know the local IP address and port number the server listens
on. Once that information is found, you only need to add a line to the
NAPT.INI file stating whether it is a TCP server or a UDP server. The line
is as follows:
tcp_server=: ex. 10.64.1.1:21
udp_server=: ex. 10.64.1.2:6667
And as you add servers, just add another line stating whether it is a TCP or
UDP server and the IP address and port information. The way the Internet
Extender will use this information, is it will set aside the port numbers
you specified and when an incoming request comes to the Globally unique IP
address given by your ISP, and the port number matches, it will map that
request to the server machine it references. The only limitation is that
you cannot have more than one server using the same port number. If your
servers are configurable and you have two of the same type (ie. FTP servers)
then you will have to change the port number that one of the servers listens
on for them to both function properly.
How to Access the Internet with the Internet Extender
The way that the program is designed to function is as a gateway to
the Internet. The machine is multi-homed, meaning either 2 Network
Interface Cards or a Network Interface Card and a Modem. Each device is
connected to a separate network with its own addressing scheme. Each
network also only sees the card and respective IP address that it is
physically connected to. The software is designed to do the translation
between the two separate networks. The machines on the Local Area Network
should treat the Internet Extender as their Gateway to the Internet.
In order for this to happen, each machine needs to be simply configured to
direct all traffic not intended for the Local Area Network to the Internet
Extender. This is done by telling each machine that the Gateway address is
the local IP address that was statically assigned to the Internet Extender.
The program will receive all requests from the local network, translate the
addressing information and forward it onto the Internet and vice-versa. So
the only configuration necessary for each local client machine is the
gateway address which is the local IP address of the Internet Extender.
I would like to thank Dr. Dan Lewis, Head of the Computer Engineering
Department at Santa Clara University, for his countless hours of work that
he put into me and the program itself. Without his expertise and help, the
program would not have anywhere near the functionality that it does at this
point. I appreciate everything that he has done for me as a student, and
everything he has done on the program itself. Thank you.
Lastly, I would like to thank Antonio Lopez Molero for writing the PPPD for
DOS packet driver and the people that contributed to its success. The PPP
driver has worked flawlessly and it has contributed to the success of the
program because I can count on it functioning properly. You can visit the
website for the PPPD program at:
You can find packet drivers for your specific Ethernet Cards at their
respective manufacturer's websites or at the Crynwr ftp server:
You can visit the Internet Extender's website for updates and
troubleshooting tips at: