Build A Router With A 386 And A Floppy Disk, Part 2

FreeSCO’s nicest feature is the sensible default firewall
configuration. Log into the setup screen, and select a) Advanced
Settings. To activate the built-in firewall, select 11, On/Off
NAT/Firewall.:

Enable IP masqerade: y.

If the nodes on your LAN have routable IP addresses, this won’t work-
otherwise it must be enabled.

Follow the steps in Part 1, turn on the firewall, and you’re
done. Instant firewall/router. As nice as the defaults are, there may
be times when manual editing is necessary. Look in the /router/rc
directory. Warning: do not edit with Notepad, or any Windows word
processor. Use a Linux/Unix text editor, or a real text editor for
Windows, like GNU Emacs.

Installing NICs

The most common problem with FreeSCO is having the right modem
drivers. It supports and automatically configures many popular modems
‘out of the box’, but newer drivers must be installed manually. 3Com
cards are the easiest, cards based on the 3c509 and 3c59x chipsets
will work without hassle. PCI cards based on the Realtek 8129/8139,
and DEC 21040, 21041, and 21140 chips, such as DLink and Linksys, need
the rtl8139 and DEC tulip drivers, respectively. rtl8139 and tulip
have been updated, any card made in the past couple of years probably
needs the newer drivers. Look for them in the /net/new directory, in
the folder where FreeSCO was unpacked. Or download from the vendor’s
Web site. Try the drivers in /net/new first. Installing a driver is
easy itself: copy it to /router/drv, then re-run the NIC
setup. (Advanced Settings)

There is about 50k of free space on a new FreeSCO 0.2.7 floppy. Leave
20k free for DHCP. That doesn’t leave much room for installing a modem
driver. Which brings us to running FreeSCO from a hard drive. Using a
hard drive makes room for all kinds of fun projects, like running a
simple Web site or an MP3 server. There is a built-in utility for
migrating from a floppy to a hard disk. First, make a bootable hard
drive with MS-DOS. Windows 95/98 will also work. Create and boot up a
FreeSCO floppy disk, do a normal startup, and login. At the prompt
type


move2hdd

This will take a few moments- remember, floppy drives are slow. When
it is finished, shut down FreeSCO and reboot to the hard drive. At the
command prompt type


router.bat setup

Run through the configurations and you’re in business.

Running a little Web site is dead easy. In Advanced Settings, select
option 44, Control HTTP and Time Server. Choose “s,” enable service
locally,” or “y,” open to the world. A public Web site is best housed on
a standalone machine, isolated from your internal network. Create a
/www folder, with an index.html file, and store your site files
there. If you use port 80, the default, normal URL syntax will work
fine. Ports 8080 or 3000 will also work, if your users remember to
append :8080 or :3000 to the URLs.

Build A Bridge


A bridge makes sense even on a small network. Remember, Ethernet
networks are popular because of low cost, not efficiency. Packet loss
is a fact of life- all those packets racing around, colliding, and
re-sending. Dividing a small LAN into two or three segments is
financially feasible with a free product like FreeSCO, and nice way to
keep old PCs out of landfills.

Configuration is so easy you’ll dance for joy. Boot into the setup
window and choose b), Ethernet Bridge. Because a bridge tracks MAC
addresses, all you need to do is define the NICs. The physical cabling
defines the network segments. FreeSCO supports ethernet, arcnet, token
ring, and arlan network cards; the hardest part of building a bridge
is making sure your router NICs have Linux drivers.

Dialup

FreeSCO contains some interesting dialup tools. It reminds me of the
good old days of ProComm Plus- remember Bulletin Board Services? Most
of them were computers in some enthusiast’s bedroom, with a modem line
or two. ProComm made this arrangement workable- configure any number
of BBS’s to visit, and it would automatically dial in sequence, until
it found one that wasn’t busy. Another nice feature of the good old
days was batch file downloads. Select a list of files, go to bed, and
ProComm would download them all in sequence, then politely hang
up. Disconnected midway? No problem, auto-redial and pick up where it
left off. Some things were better in the olden days.

FreeSCO is not nearly that sophisticated, but it will manage an entire
list of dialup connections. There are still a lot of small businesses
that cannot get affordable high-speed Internet access, and must rely
on dialup. Some keep two dialup accounts, one for backup. Some dial
directly to branch offices for batch processing and database
updates. so they have several numbers and processes to track. FreeSCO
can be set to hang up after a specified length of time with no packet
activity, and a person skilled at writing scripts can automate all the
dialup/hangup functions. (See Resources for more on managing
dialup/PPP in Linux.)

Warning: Beware the Winmodem. Winmodems, or software-controller
modems, are nothing but trouble for any non-Windows OS. I’m not fond
of them for Windows machines either. Be sure to use a genuine
hardware-controller modem. Most PCI modems are Winmodems. An external
serial-port modem is always a real modem, plus you get to see the
blinky lights.

FreeSCO has a dial-in access option. Access can be restricted on a
schedule, for example shut down on evenings and weekends. (The root
user can always dial in). Access can be restricted to the router only,
or to the entire LAN.

FreeSCO Administration

FreeSCO has a nice Web interface, as well as telnet and console
access. Do NOT use telnet anywhere but locally, it sends passwords in
cleartext. To run a FreeSCO box headless, I recommend the Web
interface. Access it via any client on the LAN with
‘http://routerIP:82’, for example http://10.0.0.1:82. Configuration
options are local only, or remote access over the Web.

Resources:


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Carla Shroder

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