PC Press: Internet/PC_PRESS.ISO/software/dos/misc/inar-100.exe/README

Text File | 1995-05-21 | 8.5 KB | 191 lines

Documentation to INAR 1.00 (InterNet Access Router)
===================================================

INAR is a fast, easy to configure freeware package that makes a
dedicated IP router out of any 80x86 PC running MS-DOS. To communicate
with the network interface hardware it uses packet drivers that comply
with FTP Software, Inc's packet driver specifications (Rev. 1.09). If
you have more than one computer at your site and want to connect your
LAN segment to the Internet and/or other LAN/WAN segments, this
package is for you!

Here's a list of INAR's most prominent features:

  - Up to eight interfaces.
  - The router component is written in assembler so it is very fast.
  - Propagates routing information via RIP (incl. "poisoned reverse").
  - Selective default route propagation.
  - Interfaces and static routes can be marked as hidden (to RIP) and
    unreachable.
  - Transient static routes to provide boot-time default routing
    until RIP takes over.
  - Supports static routes with variable subnet masks in the same
    IP net to ensure economic use of precious Internet IP numbers.
  - Allows source routes to enforce local routing policies.
  - Source IP address (reverse route) checking to enhance network
    security.
  - Proxy ARP (for all known routes).
  - Global broadcast forwarding between subnets of the same IP net.
  - Can send status messages to a UNIX syslog daemon.
  - BOOTP forwarding.
  - ISDN and point-to-point interfaces do not need an extra IP address.
  - Multiple transmission protocols and dialin/dialout links on the
    same ISDN interface.
  - A single non-cryptic, easy-to-understand configuration file for
    all software components.
  - Comes with packet drivers for the most common ethernet cards as
    well as with drivers for ISDN and SLIP/CSLIP.
  - Includes sample config files for the most common cases.

The router component was derived from the very popular PCroute. Many
thanks to Vance Morrison ([e-mail]) for releasing the
original version some years ago, and for giving me (Uwe Doering,
[e-mail]) permission to work on it and release my
version to the public as well. The configuration program (CF.EXE),
which holds all the parts of this package together, was written
by me from scratch.

The ethernet packet drivers that are part of this distribution have
been taken from the Crynwr Software ([e-mail]) collection
(PKTD11).

The ISDN driver (ISPA 1.8.6, with hardware independent CAPI interface)
was developed by Herbert Hanewinkel ([e-mail]).

The author of the SLIP/CSLIP drivers (SLIPPER 1.5) is Peter R. Tattam
([e-mail]).

Note that the copyrights of the original authors stay intact and aren't
affected in any way by the INAR distribution. However, the INAR package
as a whole can be freely copied and used.

As you can see, this package has several authors. I decided to not
re-invent the weel but to rather concentrate on areas that were not
so well covered, that is, enhancing the IP router and writing a
configuration program. The idea was to add a selected set of packet
drivers and roll out a package that would be almost plug-and-play.


WHERE TO FIND WHAT?
-------------------

INAR 1.00 is available via anonymous FTP from ftp.fu-berlin.de
(160.45.10.6), file `/pc/msdos/network/inar/inar-100.exe' (self-
extracting LHA file).

The INAR distribution unpacks to a directory tree:

    BIN        (executable programs)
    DOC        (documentation to the various parts)
    SAMPLES    (sample config files for the most common cases)
    SRC        (source code, if available)


WHY DO I NEED AN IP ROUTER?
---------------------------

At larger sites with many computers you can't connect all computers to
the same network segment. The number of connected devices is limited
because you wouldn't want to have the data traffic of all computers on
a single segment. The bandwidth of an Ethernet segment, for instance,
is only 10 MBit/s and with enough computers you could easily saturate
the network so that noone gets his work done anymore.

To avoid these problems, one usually splits the Local Area Network
(LAN) into separate segments. Each segment gets its own set of IP
network numbers and they are connected to each other by IP routers.
An IP router passes IP packets from one segment to another only if
the sending and the receiving device are on different segments while
the data traffic between devices on the same segment is kept local.
Additionally, if an IP router is connected to the Internet via a
point-to-point connection, it acts as a concentrator for the Internet
data traffic which it transfers over a communication line.


HOW TO SET UP THE ROUTER
------------------------

You need a single configuration file that contains all the informations
about the router and the packet drivers. The configuration syntax is
shown in the file `SYNTAX.DOC' and is described in detail in the file
`CONFIG.DOC'. Also, there are sample config files for common cases that
you may want to use as a starting point.

After you have edited the config file to reflect your local conditions
you just need to run the configuration program (CF.EXE) with the name
of your config file as the argument. For instance

    CF CONFFILE

The configuration program generates the files `P?.CFG', `INAR.BAT'
and, if you use ISDN, the files `ISPA?.CFG'. Look into `INAR.BAT'
and make sure that all programs that are called in this batch file
are present in the directory in which you want to run INAR.

Now prepare the computer's `CONFIG.SYS' and `AUTOEXEC.BAT' files in a
way that it starts everything that is necessary to run INAR. For
instance, make sure that if you use ISDN, the CAPI driver that comes
with the ISDN card is started before you run INAR. When everything is
in place, add the lines

    CD \INAR
    CALL INAR

to the end of the `AUTOEXEC.BAT' file. For this example I've assumed
that all INAR files are located in the `INAR' subdirectory. Now you
can reboot, and if you didn't make any errors INAR should start
automatically and your IP router is up and running.

To test it you should start with `ping'ing the IP addresses of the
router's interfaces, and if this works, try to reach hosts connected
to the other interfaces. Also, if you use the Routing Information
Protocol (RIP), verify that your computer's routing table contains
entries that were provided by the router. Under UNIX, you do that
with `netstat -rn'. Note that up to 30 seconds may pass between
RIP updates, so, for instance, a routing change in a remote part
of your network will need some time until it has been propagated
to your computer.


CONNECTING TO THE INTERNET
--------------------------

All computers that communicate directly with the Internet have to have
official Internet IP numbers. There are Internet providers all over
the world who will sell you Internet connectivity. So the first step
is to find a provider who is willing to connect you. This provider
gives you a range of official IP numbers, a netmask matching the range
of numbers and the IP address of the gateway router he connects you
to.

You can now assign each of the computers on your LAN (plus the INAR
router itself) a unique IP address from the range of IP numbers you've
got from the provider. Note that the first and the last address in this
IP net must not be used. The last address is the broadcast address of
your IP net. RIP, for instance, propagates its routing informations
via this broadcast address. So if you want to use RIP you should make
sure that all computers on the same LAN segment (including your INAR
router) have an identical netmask and broadcast address.

At this point, you need to set up the connection to the Internet
provider. If you are connected via the analogue telephone network you
could use the SLIP/CSLIP driver (without on-demand dialup) that comes
with INAR. If you have an ISDN connection you may want to use the ISPA
driver (with on-demand dialup) bundled with INAR. You then have to
make sure that your ISDN driver "speaks" the same transmission
protocol as your provider's gateway. With ISPA you have the choice
between serveral protocols (look at the ISPA docs and the sample
config files).

For further provider dependent informations please ask your Internet
provider. After all, if it is a commercial provider, you pay him to
support you.


BUG REPORTS
-----------

Please send bug reports to `[e-mail]'. Although my
spare time is limited, I'll try my best to answer as many emails
as I can.