Casema Wanadoo cable modem HOWTO

        by Siward de Groot, updated 2004 august 14


whatis :

This describes how i got a working internet connection
  with Casema (tv-cable network connection), Wanadoo (internet provider)
  and Debian (linux distribution)

general :

I live in Utrecht, Netherlands,
  there is 1 tv-cable exploitation company here : casema
Together with Wanadoo (which has new, much improved leadership)
  they offer permanent internet connection with 256 kb/s (==32 kB/s) downstream
  for euro 19.95 /month (soon to be speeded up to 512 kB/s)

Up till now i had a dialup account, at 8 kB/s max,
  which is not suitable for permanent connection,
  and which cost me (on average) 30 euro/month
    plus cost of having a telephone at all.

I think using internet for telephone has future, and using telephone for internet is of past,
  and i like to not spend overly much money,
  so i called casema to get connected.

First i have to subscribe to casema's tv-signal distribution (at euro 8.50 /month),
  otherwise they will not allow me to get any of their internet products,
  so casema's helpdesk tells me.
Why anyone would want to watch tv when they can work on debian is beyond me,
  but paying this amount would be justified if
  antennas cost much less than cables (which i think is true),
  as i do use these cables.
anyway, casema's offer is much more attractive than what i can get from phone company,
  so first i order tv signals to be delivered.
  this takes a week or so.

When this is completed, i verify that tv connection works,
  and call casema helpdesk again, to order internet.
Their cheapest offer is called 'broadband box',
  (because cardboard box that equipment comes in is only thing that becomes your property)
  and that is what i order.

I have already been told that wanadoo helpdesk does not support linux,
  but i have seen some HOWTOs on web, so i think i can get it working.
As it turns out, HOWTOs on web describe a situation that no longer exists,
  where l2tp protocol is used,
  but as casema's website tells me, they stopped using that in march 2004.
Fortunately, though helpdesk cant help me with setting up linux, as most people there dont have that,
  some of people on helpdesk (2nd line presumably) do know a lot about networking,
  and are so friendly to provide technical details that enable me to get it working.
Having an uptodate HOWTO would still be easier, however,
  which is why i publish my experiences here.
  I hope you'll find it usefull.

An appointment is made for delivery of broadband box to my home,
  it is delivered on a weekday (i am single, so i take a day off work for this)
  and i have to identify myself with my passport.

installing hardware :

Broadband box is good, complete, with excellent instructions on how to connect to tv cable.
It contains
  a short tv coaxcable
  a splitter
  a slightly longer coaxcable
  a modem
  a network cable
  a network card
  miscellaneous trivia
  a leaflet saying howto connect above components
  a booklet saying howto setup internet for windows and some versions of mac os

Short coaxcable connects splitter to tv-signal outlet.
Splitter probably filters lower 50 MHz of videoband (no transmissions there)
  to outlet for modem, and rest to outlet for tv.
Outlet for modem is connected by slightly longer coaxcable to modem.
Modem translates signals on low band of tv cable to ehternet-type messages
  (there is probably another modem on casema end of tv cable,
   that modem doing opposite : translating ethernet to tv-cable signal).
Network cable connects modem to network card.
Network card is to be plugged in to my pc.

I screw splitter to wall near tv-signal outlet, and connect it's cables.

Modem is a: motorola "surfboard" SB5100E .
When it's input cable is connected, and it's powersupply adapter plugged into 220V socket,
  lights start to blink,
  until after a couple of minutes all green lights are constantly lit,
    and yellow 'activity' light is flashing ;
  this is good.

Network card is a "SMC 10/100Mbps PCI-Netzwerkkarte", type LN40
i power down pc, and disconnect power cord from pc,
  then i open pc case, find an unused pci slot,
  remove small metal cover from case near that pci slot;
    (networkcard's connectorplate will take it's place),
  and firmly press network card into slot.
Then close case, reconnect power cable, and power up.

installing software :

When network card is plugged in, linux needs a driver for it.
If this driver is compiled into kernel, then it be detected at boot time (when pc is "turned on"),
  and you can skip rest of this paragraph.
if it is not compiled in, then it must be loaded as a kernel module,
  which you can do by hand with: insmod <modulename>
  but you need to get networkcard detected at boot,
  so you need to tell linux to load driver at boot,
  which is done by adding driver's name into /etc/modules .

Network card i got in broadband box was recognized as a realtek 8139 card
  (on box it says "SMC LN40 10/100Mbps PCI-Netzwerkkarte")
  and driver for it is "8139too",
  which is compiled into (2.4) kernel of stock Debian stable ("woody").

Now that kernel can find information on which drivers to load at boot time (if any),
  time has come to reboot computer.
This can be done with : shutdown -r now

When computer is up and running again,
  i look at messages that were printed by kernel at boot time
  by doing: dmesg | grep eth
For me this resulted in:
  eth0: RealTek RTL8139 Fast Ethernet at 0xcc81c800, 00:0b:2b:12:3d:48, IRQ 5
  eth0: Identified 8139 chip type 'RTL-8139C'
(You could try "dmesg | grep 8139" also, or look through /var/log/dmesg, or use lspci).

Now kernel has detected network card, and has loaded driver for it,
  which it will call when a message is to be sent,
Networkcard will generate an interrupt when it needs attention,
  which is whenever a message is received,
  and kernel then reacts to interrupt by calling driver.

Network cable must be connected between network card and modem.

One of two lights on network card blinks rapidly, indicating transfer of information ;
  to see what that information is, i want to use tcpdump,
  but interface is not 'up' yet (i think that means that it has not been enable by root),
  and when i try to do 'ifup eth0' it fails with "Ignoring unknown interface eth0=eth0",
  but i find that i can bring interface up by doing ifconfig -i eth0
This says that interface 'eth0' must be assigned internet address
  (which is a special address that is used when real address is unknown).
If i now do ifconfig -a
  (-a means show all interfaces, even inactive ones),
  then result is :
    eth0 Link encap:Ethernet HWaddr 00:0B:2B:12:3D:48
    (plus some not statistics)
So now interface is up and running, and tcpdump can be used on it ;

I notice that mtu is set to default value of 1500,
  while wanadoo booklet says that it should be 1496,
  so i first correct this by ifconfig -i eth0 mtu 1496

Now use tcpdump : tcpdump eth0 > /tmp/tcpdump
Kill tcpdump process after a couple of seconds by control-c
  (that is: press control key, press c key, release c key, release control key)
  otherwise tcpdump forever continue to write to /tmp/tcpdump file.
Inspecting that file with an editor reveals that modem is sending ARP requests to network card ;
  probably modem on casema's side of tv-cable is connected to a switching hub,
  that sends to modem on my side of cable any packets that are addressed to my ip address,
  plus any packets that are to be sent to everybody (this is called a 'broadcast'),
  and as i dont have an ip address yet, all i see are arp broadcasts.
Receiving these arp requests means that modem is functioning correctly
  (at least in direction from wanadoo network to my network card).

As helpdesk tells me (i can not verify this),
if a browser is launched now, then it displays casema's account-activation webpage.
If so, then activate your account with this.
If not, then call helpdesk, and ask them to activate account.

Next step is getting an ip address from wanadoo
  (an ip address is a numeric address as used by internet protocol (ip)).
This is done by using dhcp (dynamic host configuration protocol).
Debian has 2 programs that can do this : dhclient and pump ;
  i use dhclient, which is in package 'dhcp-client'.
So to get an ip address, i do: dhclient eth0
dhclient uses a broadcast to contact a dhcp server on ethernet it is connected to,
  and if all went well, dhcp server grants dhclient use of an ip address for a limited time.
dhclient writes details of this grant to file /var/lib/dhcp/dhclient.leases
  and that file can be read with an editor to see if all went well (it is easily readable).

dhclient on my system automatically set up system correctly,
  so that i had working internet from this moment on,
  but i first present you with some more intermediate steps to verify correct behaviour :

* 'ifconfig' should now show internet address for eth0
  if that address should happen to be in 10.x.y.z range,
    then that means that you need to call helpdesk to get them to change settings of modem
    as this is address range that you got before march 2004, when wanadoo uas still using l2tp.
  they dont use that anymore (hooray!),
    so now an address in range 82.x.x.x or something nearby that is used
    (these addresses can be used directly on internet, 10.x.x.x can not)
* try 'ping' (this verifies operation of ping program)
* try 'ping localhost' (identical to ping
* try pinging router (find router's numeric address from /var/lib/dhcp/dhclient.leases)
* try 'ping' (that is numeric address of
* try 'ping'

If pinging localhost or failed, then configuration of your pc is broken;
  installing debian anew should get your system in a sane state again.
If pinging router didnt work, then either router is down, or router never received message,
  perhaps message never left your pc,
  try route to see current contents of kernel's routing table.
  On my system, 'route' produces :
    Destination  Gateway         Genmask       Flags Metric Ref Use Iface *      U     0      0   0   eth0
    default      c529da001.cable       UG    0      0   0   eth0

  First line says that is ip address of a network,
    messages to this network do not need to be sent via a gateway (aka router)
    (reason is that this is address of ethernet to which modem connects me),
    so it can simply be reached through interface eth0 .
  Second line says that all internet messages whose destination is not in another route entry
    should be sent to router c529da001.cable .
    If this looks a bit strange, try route -n instead of plain route ;
      -n option makes route show numeric addresses (instead of names).
If pinging debian numerically didnt work, then router didnt send ping message on ;
  check router's ip address ; if it is correct, then call helpdesk (politely!).
If only last ping failed, then domainname resolution is broken ;
  check /etc/resolv.conf for current settings, and change it by hand if needed
    (dns server ip adresses are in leases file).
If all these worked, then internetconnection is working.

todo :

I still need to find out how to make dhclient set mtu correctly.
need to check /etc/network/interfaces and man 5 interfaces, to get ifup/ifdown working

using wanadoo account :

When i tried to use my new email address, or ftp to my homepage,
  or to log in to change my settings on wanadoo site,
  my username/password combi was not recognized.
Casema's webpages with "portal" structure dont work at all.
  they dont display information, not even with java and javascript enabled globally.
So i called helpdesk (0900-8896 ; 08u00-22u00, weekend 10u00-16u00),
  they tell me that i first need to set my 'hoofd email adres',
  so i visit ,
  this gets redirected to ,
  which presents a form where 'gebruikersnaam' and 'wachtwoord' must be filled in,
  except that it only works if instead of 'gebruikersnaam' i fill in hoofd-email-adres,
    (which is gebruikersnaam plus .nl extension, in my case).
  then i am shown a page where i can change my email address, and i change it to .

mail :

I use exim and fetchmail for distributing/sending and retrieving mail, so i need to :
  tell fetchmail about my new email account,
    normal way to do that is with fetchmailconf, but i do it by hand :
    i add these lines to ~/.fetchmailrc :
      poll with proto POP3
        user '' with pass 'secretpassword' there is 'root' here
  and tell exim to use wanadoo's smtp server for sending mail :
    (running my own mailserver is not allowed by casema/wanadoo)
    i do this by hand too, i visit /etc/exim/exim.conf with my editor,
    find line that contains (smtp server of dialup account that i used untill now)
    and change it to
  i also need to change exim's address rewriting,
    until now, if it got a mail FROM root@localhost, it rewrites FROM address to
    finding that freeler address in /etc/email-addresses ,
    so i look in /etc/email-addresses, and change all freeler addresses there into wanadoo addresses.
I test fetchmail configuration by doing fetchmail -v
  which shows (among otheres) :
    fetchmail: 5.9.11 querying (protocol POP3) at Sun Aug 15 12:56:32 2004: poll started
    fetchmail: POP3< +OK connected to pop3 on 6104
    fetchmail: POP3> USER
    fetchmail: POP3< +OK name is a valid mailbox
    fetchmail: POP3> PASS
    fetchmail: POP3< +OK user exist with that password
Then i simply test exim by sending a mail to
  (exim does have verbose debugging options that are suitable for this, but this way is simpler)
  it worked right away.

homepage :

Now test ftp by trying to upload these pages to with gFTP ...
  (port 21, user , password as before)
  it works, i found my homepage (file index.html that i uploaded) at

Apparently wanadoo homepages can use a small number of fixed cgi scripts,
  available scripts are : guestbook, mailto, counter, imagemap, and redirect script ;
  for more information about these scripts, try this :

  ha, that is fun :-)

For more advanced scripting, i can use apache/mySQL ofcourse, since i am now online permanently,
  but for now cgi is nice, and i dont have to study apache.

domainname :

Wanadoo's pages also report availablility of domainname registration,
  and contain a link to for that (euronet is a wanadoo company).
Visiting euronet's webpages, only reference to registering a domainname i found was
  an offer for webhosting+domainname, at 20 euro /month (rather expensive, i think).
Fortunately, there is nothing stopping me from registering a domainname elsewhere,
  i found , where a domainname costs $ 7.95 /year , and they have paypal ,
  so you may in future find this page under an other name.
I think i can simply specify wanadoo's dns servers when i register a domainname,
  though, as helpdesk informs me, these dont have non-numeric names,
  but i guess i'll succeed anyway.
Aha, tunrns out helpdesk was wrong :
  host -\> domain name pointer
  host -\> domain name pointer
  host -\> domain name pointer

feedback :

If you find that this howto helped, or that it contains errors or omissions,
  please let me know by sending me an email

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