1sb1000 is a module network device driver for the General Instrument (also known
   2as NextLevel) SURFboard1000 internal cable modem board.  This is an ISA card
   3which is used by a number of cable TV companies to provide cable modem access.
   4It's a one-way downstream-only cable modem, meaning that your upstream net link
   5is provided by your regular phone modem.
   7This driver was written by Franco Venturi <>.  He deserves
   8a great deal of thanks for this wonderful piece of code!
  12Support for this device is now a part of the standard Linux kernel.  The
  13driver source code file is drivers/net/sb1000.c.  In addition to this
  14you will need:
  161.) The "cmconfig" program.  This is a utility which supplements "ifconfig"
  17to configure the cable modem and network interface (usually called "cm0");
  202.) Several PPP scripts which live in /etc/ppp to make connecting via your
  21cable modem easy.
  23   These utilities can be obtained from:
  27   in Franco's original source code distribution .tar.gz file.  Support for
  28   the sb1000 driver can be found at:
  33   along with these utilities.
  353.) The standard isapnp tools.  These are necessary to configure your SB1000
  36card at boot time (or afterwards by hand) since it's a PnP card.
  38   If you don't have these installed as a standard part of your Linux
  39   distribution, you can find them at:
  43   or check your Linux distribution binary CD or their web site.  For help with
  44   isapnp, pnpdump, or /etc/isapnp.conf, go to:
  50To make the SB1000 card work, follow these steps:
  521.) Run `make config', or `make menuconfig', or `make xconfig', whichever
  53you prefer, in the top kernel tree directory to set up your kernel
  54configuration.  Make sure to say "Y" to "Prompt for development drivers"
  55and to say "M" to the sb1000 driver.  Also say "Y" or "M" to all the standard
  56networking questions to get TCP/IP and PPP networking support.
  582.) *BEFORE* you build the kernel, edit drivers/net/sb1000.c.  Make sure
  59to redefine the value of READ_DATA_PORT to match the I/O address used
  60by isapnp to access your PnP cards.  This is the value of READPORT in
  61/etc/isapnp.conf or given by the output of pnpdump.
  633.) Build and install the kernel and modules as usual.
  654.) Boot your new kernel following the usual procedures.
  675.) Set up to configure the new SB1000 PnP card by capturing the output
  68of "pnpdump" to a file and editing this file to set the correct I/O ports,
  69IRQ, and DMA settings for all your PnP cards.  Make sure none of the settings
  70conflict with one another.  Then test this configuration by running the
  71"isapnp" command with your new config file as the input.  Check for
  72errors and fix as necessary.  (As an aside, I use I/O ports 0x110 and
  730x310 and IRQ 11 for my SB1000 card and these work well for me.  YMMV.)
  74Then save the finished config file as /etc/isapnp.conf for proper configuration
  75on subsequent reboots.
  776.) Download the original file sb1000-1.1.2.tar.gz from Franco's site or one of
  78the others referenced above.  As root, unpack it into a temporary directory and
  79do a `make cmconfig' and then `install -c cmconfig /usr/local/sbin'.  Don't do
  80`make install' because it expects to find all the utilities built and ready for
  81installation, not just cmconfig.
  837.) As root, copy all the files under the ppp/ subdirectory in Franco's
  84tar file into /etc/ppp, being careful not to overwrite any files that are
  85already in there.  Then modify ppp@gi-on to set the correct login name,
  86phone number, and frequency for the cable modem.  Also edit pap-secrets
  87to specify your login name and password and any site-specific information
  88you need.
  908.) Be sure to modify /etc/ppp/firewall to use ipchains instead of
  91the older ipfwadm commands from the 2.0.x kernels.  There's a neat utility to
  92convert ipfwadm commands to ipchains commands:
  96You may also wish to modify the firewall script to implement a different
  97firewalling scheme.
  999.) Start the PPP connection via the script /etc/ppp/ppp@gi-on.  You must be
 100root to do this.  It's better to use a utility like sudo to execute
 101frequently used commands like this with root permissions if possible.  If you
 102connect successfully the cable modem interface will come up and you'll see a
 103driver message like this at the console:
 105         cm0: sb1000 at (0x110,0x310), csn 1, S/N 0x2a0d16d8, IRQ 11.
 106         sb1000.c:v1.1.2 6/01/98 (
 108The "ifconfig" command should show two new interfaces, ppp0 and cm0.
 109The command "cmconfig cm0" will give you information about the cable modem
 11210.) Try pinging a site via `ping -c 5', for example.  You should
 113see packets received.
 11511.) If you can't get site names (like to resolve into
 116IP addresses (like, be sure your /etc/resolv.conf file
 117has no syntax errors and has the right nameserver IP addresses in it.
 118If this doesn't help, try something like `ping -c 5' to
 119see if the networking is running but the DNS resolution is where the
 120problem lies.
 12212.) If you still have problems, go to the support web sites mentioned above
 123and read the information and documentation there.
 127Common problems:
 1291.) Packets go out on the ppp0 interface but don't come back on the cm0
 130interface.  It looks like I'm connected but I can't even ping any
 131numerical IP addresses.  (This happens predominantly on Debian systems due
 132to a default boot-time configuration script.)
 134Solution -- As root `echo 0 > /proc/sys/net/ipv4/conf/cm0/rp_filter' so it
 135can share the same IP address as the ppp0 interface.  Note that this
 136command should probably be added to the /etc/ppp/cablemodem script
 137*right*between* the "/sbin/ifconfig" and "/sbin/cmconfig" commands.
 138You may need to do this to /proc/sys/net/ipv4/conf/ppp0/rp_filter as well.
 139If you do this to /proc/sys/net/ipv4/conf/default/rp_filter on each reboot
 140(in rc.local or some such) then any interfaces can share the same IP
 1432.) I get "unresolved symbol" error messages on executing `insmod sb1000.o'.
 145Solution -- You probably have a non-matching kernel source tree and
 146/usr/include/linux and /usr/include/asm header files.  Make sure you
 147install the correct versions of the header files in these two directories.
 148Then rebuild and reinstall the kernel.
 1503.) When isapnp runs it reports an error, and my SB1000 card isn't working.
 152Solution -- There's a problem with later versions of isapnp using the "(CHECK)"
 153option in the lines that allocate the two I/O addresses for the SB1000 card.
 154This first popped up on RH 6.0.  Delete "(CHECK)" for the SB1000 I/O addresses.
 155Make sure they don't conflict with any other pieces of hardware first!  Then
 156rerun isapnp and go from there.
 1584.) I can't execute the /etc/ppp/ppp@gi-on file.
 160Solution -- As root do `chmod ug+x /etc/ppp/ppp@gi-on'.
 1625.) The firewall script isn't working (with 2.2.x and higher kernels).
 164Solution -- Use the ipfwadm2ipchains script referenced above to convert the
 165/etc/ppp/firewall script from the deprecated ipfwadm commands to ipchains.
 1676.) I'm getting *tons* of firewall deny messages in the /var/kern.log,
 168/var/messages, and/or /var/syslog files, and they're filling up my /var
 171Solution -- First, tell your ISP that you're receiving DoS (Denial of Service)
 172and/or portscanning (UDP connection attempts) attacks!  Look over the deny
 173messages to figure out what the attack is and where it's coming from.  Next,
 174edit /etc/ppp/cablemodem and make sure the ",nobroadcast" option is turned on
 175to the "cmconfig" command (uncomment that line).  If you're not receiving these
 176denied packets on your broadcast interface (IP address xxx.yyy.zzz.255
 177typically), then someone is attacking your machine in particular.  Be careful
 178out there....
 1807.) Everything seems to work fine but my computer locks up after a while
 181(and typically during a lengthy download through the cable modem)!
 183Solution -- You may need to add a short delay in the driver to 'slow down' the
 184SURFboard because your PC might not be able to keep up with the transfer rate
 185of the SB1000. To do this, it's probably best to download Franco's
 186sb1000-1.1.2.tar.gz archive and build and install sb1000.o manually.  You'll
 187want to edit the 'Makefile' and look for the 'SB1000_DELAY'
 188define.  Uncomment those 'CFLAGS' lines (and comment out the default ones)
 189and try setting the delay to something like 60 microseconds with:
 190'-DSB1000_DELAY=60'.  Then do `make' and as root `make install' and try
 191it out.  If it still doesn't work or you like playing with the driver, you may
 192try other numbers.  Remember though that the higher the delay, the slower the
 193driver (which slows down the rest of the PC too when it is actively
 194used). Thanks to Ed Daiga for this tip!
 198Credits:  This README came from Franco Venturi's original README file which is
 199still supplied with his driver .tar.gz archive.  I and all other sb1000 users
 200owe Franco a tremendous "Thank you!"  Additional thanks goes to Carl Patten
 201and Ralph Bonnell who are now managing the Linux SB1000 web site, and to
 202the SB1000 users who reported and helped debug the common problems listed
 206                                        Clemmitt Sigler
 208 kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.