Configuring Alcatel as forward modem

Introduction

My ISP has provided me with a Alcatel SpeedTouch Home ADSL modem. I used PPTP to conntect (with my FreeBSD gateway) initialy as my ISP suggested. This was not a stable setup and the link was down a lot. I then upgraded my modem (though a hack) and used NAT, but it dropped a lot of packets during high loads. You have to have a static IP.

My current setup doesn't use PPTP nor NAT and is very stable. I use a option called SIP_SPOOF which changes the external interface in sucha way that routing packets though to my FreeBSD gateway is posible. This setup only works if your ISP uses PPPoA and your ADSL modem is capable of this trick.

You risk destroying your modem with this procedure. Don't follow this procedure if you whish to stay on the safe. During the configuration you can lose the internet connection, so make a copy of this tutorial.

At this thime I assume that your modem can be accessed though 10.0.0.138 and your computer has the ip adress 10.0.0.150, network mask 255.255.255.0 and as default gateway: 10.0.0.138.

Alcatel SpeedTouch Pro

This section will help you upgrade you Alcatel SpeedTouch Home to a Alcatel SpeedTouch Pro modem. You will find a challange string and use it to get your expert password. Onces you have this you can upgrade your modem.

Connect to you modem with telnet
```
telnet 10.0.0.138
```

Find the challenge string using the 'EXPERT' or 'td prompt' command. The line with SpeedTouch in it is the challenge string.

=>EXPERT
========================DISCLAIMER=========================
Access to expert mode is intended for qualified personnel
only. Press ENTER to return to user mode.
=====================END=OF=DISCLAIMER=====================

'SpeedTouch (00-90-DB-4A-FA-AF)'
Password :

Feed the challange string to the expert password generator.
Go back to your telnet session and feed the expert password to your modem.
No execute the command 'rip' followed by 'drv_read 2 1 b'. This will return "the data in hex is : 8604 or 8704.
Now chance the 4 in a six with 'drv_write 2 1 b 8606' or 'drv_write 2 1 b 8706' depending on your version.
Finaly reboot your modem with 'reboot'. You now have a Alcatel SpeedTouch Pro ADSL modem.

Configure Modem

Wait a few minutes and then open a connection to you modem (10.0.0.138) with you internet browser in a second window. And make the following changes.
Remove all entries from the Bridge, PPTP, CIP, PPP and Phonebook pages. Write down your VPI/VCI setting do. Also disable DHCP and DNS.
Open the Phonebook and create a new entry with the following settings: Name: SIP_SPOOF VPI: 8 VCI:48 Type:ppp.
Open the PPP page and configure now the new entry. Fill in the user and password. Keep NAT disabled. Fill 192.168.255.1 in for Local IP and set the mode to allways-on. The final settings are: LCP echo on, PAP off and ACCOMP on.
Press save all to make it permanent. You can wait with this, if you like, until the end of the following section.

Configure FreeBSD Gateway

Now open /etc/rc.conf and do the following:

Remove or comment out the defaultrouter line.
Configure you network cards
Add a number of static routes.

An example:

#defaultrouter="10.0.0.138"
ifconfig_xl0="192.168.1.1 netmask 255.255.255.0 media 100baseTX mediaopt full-duplex"
ifconfig_xl1="[EXTERNAL_IP] netmask 255.255.255.255"
static_routes="spd mxs"
route_spd="-net 10.0.0.138 -iface [EXTERNAL_IP] -cloning"
route_mxs="default 10.0.0.138"

Final notes

I like to encourage you to contact me, if you have questions or feedback about this howto. I can be contact my though the feedback link on top.

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