Using ISDN in FreeBSD

When I had to move from my beloved cable modem link to areas so rural that ADSL was but a faint promise from the big city, I decided that ISDN was the least I should treat myself to, in ways of bandwidth. OK, there's isdn4bsd, (ISDN for FreeBSD) which is the utility to use if you have installed an internal ISDN card, but rumour (and thousands of disgruntled FBSD users) find isdn4bsd somewhat difficult to configure.

The easier alternative is to use an external ISDN modem, a terminal adapter. The T/A will use the traditional PPP protocol to communicate with the network, and can be set up the same way. The difference (hopefully) is the increase in speed (64 or 128 K/second).

My T/A is a Dynalink TAS 400E, and this is significant mainly concerning the modem initialization string in the /etc/ppp/ppp.conf file. Other than that, most of the settings here mentioned, can be used as they are. But, as always, YMMV and you replace the values with your own, do your own footwork and look before you cross.

First

A T/A is installed the same way as an ordinary modem, the same connections and the same ports. Refer to your T/As documentation.

Files

At time of writing, I was using FreeBSD 4.4-stable. This is the files I edited for use with ISDN/PPP:

In /etc/host:

hosts bind

In /etc/resolv.conf :
(Naturally, here is where you enter your ISPs domain and primary and secondary nameserver. You knew that, right?)

domain c2i.net nameserver 193.216.1.10 nameserver 193.216.69.10

I'm not sure the options and ppp.linkup files are needed anymore, but hey.

In /etc/ppp/options:

/dev/cuaa0 115200 crtscts modem passive noipdefault defaultroute domain c2i.net

Notes:

the first line needs to refer to the device which is your modem. Set the speed as high as possible.
noipdefault means that I do not have a permanent IP address. When on a dial-up connection, neither have you
What am I babbling about? Read man ppp .

If your ISP uses PAP or CHAP authentification, you put the following in the /etc/ppp/pap-secrets or /etc/ppp/chap-secrets file:

"yourusername with your ISP" * "Password"

...but these things go in the most important file anways, namely

/etc/ppp/ppp.conf

The defaults are fine to a degree (except username, phone number and password, of course) but I hereby give you my file, with the alterations I have made.

################################################################# # PPP Sample Configuration File # Originally written by Toshiharu OHNO # Simplified 5/14/1999 by wself@cdrom.com # # See /usr/share/examples/ppp/ for some examples # # $FreeBSD: src/etc/ppp/ppp.conf,v 1.2.2.5 2001/07/13 10:55:23 brian Exp $ ################################################################# default: set log Phase Chat LCP IPCP CCP tun command ident user-ppp VERSION (built COMPILATIONDATE) # Ensure that "device" references the correct serial port # for your modem. (cuaa0 = COM1, cuaa1 = COM2) # set device /dev/cuaa0 set speed 115200 set dial "ABORT BUSY ABORT NO\\sCARRIER TIMEOUT 5 \ \"\" AT OK-AT-OK ATE1Q0 OK \\dATB4DT\\T TIMEOUT 40 CONNECT" set timeout 0 # 3 minute idle timer is the default, #0 means never time out. enable dns # request DNS info (for resolv.conf) #enable chap accept PAP #exactly what it says tele2: deny lqr set phone 150221312064 set authname myusername set authkey mypassword set openmode active 5 set ifaddr 10.0.0.1/0 10.0.0.2/0 255.255.255.0 0.0.0.0 add default HISADDR # Add a (sticky) default route

Things to note:

"ATB4DT" is the init string for the modem. The default file uses "ADTD".
the default and tele2 bit is "configuration labels". "Default" (doh) means that the values set there is read every time. But I can have more labels, for example one for each ISP I use, in which case I probably have different usernames and passwords. Configuration labels are always followed by a colon, and these lines are not indented. The others are.
The lqr and openmode thingies proved essential for me. I have no clue what these values do. Read man ppp and you will be enlightened.