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Kppp Setup

Kppp's default setting (probably?) has a bug. In the Debian branches I tested in the file /etc/ppp/peers/kppp-options, the option noauth is commented out with a hash mark (#). For dialout, the option should be present, so please remove the hash mark or add noauth to pppds standard options in /etc/ppp/options. This option for pppd just means that the address being connected to your modem is not required to authenticate itself, which makes sense here because you are not planning to let the modem log on to your computer, but you want to log on to the provider's network instead.

After fixing that, you need to tell kppp that your modem is actually connecting via UMTS or GPRS, which is an init string that has to be sent to the modem before dialing.

For your Internet connection, add

AT+CGDCONT=1,"IP","3internet"

as the Init2 string in the kppp Edit Modem Commands options (Figure 1), which differs among different providers.

Figure 1: Configuring modem settings with kppp.

For UMTS or GPRS, the number to dial is always (without the "ATD" prefix) *99# (including the asterisk and hash mark). Before your modem is ready to serve as a modem, you must unlock the SIM for this session. To do so, you either need to remove the PIN that protects the SIM Card from unauthorized use, or send the PIN once while the modem is plugged in. The modem command for this purpose can be typed directly in the kppp "terminal" that you can open in the modem command window,

AT+CPIN=1234

where 1234 is replaced by your SIM's pin number. If you mistype the number, the modem will greet you with a "PUK Pin" instead of "SIM Pin" request, which means you will have to unlock the SIM with the much longer PUK that was provided with your SIM Card. Failing authentication will result in the modem responding with something like "illegal command" to every dial attempt.

Now you are ready to connect. You can save all settings in kppp; only the PIN command above must be typed each time you remove and reconnect the modem from the computer's power, unless you disable the PIN on your SIM Card.

Wvdial

An anonymous poster on the Ubuntu forums at http://ubuntuforums.org/showthread.php?p=5569939 reports that the /etc/wvdial.conf entry shown in Listing 2 worked for him.

Listing 2

/etc/wvdial.conf

01 [Dialer Defaults]
02 Init1 = ATZ
03 Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
04 Init3 = AT^SYSCFG=2,2,3FFFFFFF,1,2
05 Init5 = AT+CGDCONT=1,"IP","3internet"
06 Modem Type = Analog Modem
07 Baud = 460800
08 New PPPD = yes
09 Modem = /dev/ttyUSB0
10 ISDN = 0
11 Stupid Mode=1
12 Phone = *99#
13 Password = three
14 Username = three
15
16 [Dialer 3g]
17 Init4 = AT^SYSCFG=14,1,3FFFFFFF,2,4
18
19 [Dialer gprs]
20 Init4 = AT^SYSCFG=13,1,3FFFFFFF,2,4

Note the different settings for fast UMTS and the slower GPRS variant. Wvdial has to be started as root to fire up pppd after connecting.

Stick Script

Question:

In the October 2008 issue of Linux Magazine, you told of the script to put Knoppix 3.5.1 onto a USB stick.

I have a 4GB (3950Kb or something) USB stick, and it is not big enough. It bombs out with an error stating that there is not enough space. What size stick do I need? I was under the impression that this type of thing could be done on a 1GB stick.

Answer:

The CD version of Knoppix is about 700MB, whereas the DVD version is over 4GB. The CD version should fit on a 1GB stick. The DVD version requires a stick of around 5GB, so the closest common size available is probably an 8GB stick for the DVD version (which I frequently use for testing USB boot compatibility).

Also, if you remaster the compressed files, please make sure the resulting size of a single file after compression does not exceed 4GB, because that is the maximum file size supported by the FAT32 filesystem, which is usually used for USB sticks.

The same limit applies for a plain ISO 9660 CD-ROM/DVD filesystem. Thus, to stay below this limit, the compressed files are split into two parts on the Knoppix DVD, then they are merged via UnionFS/AuFS during the boot process.

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