25.2. Configuring an ADSL or T-DSL Connection

25.2.1. Default Configuration

Currently, SUSE LINUX supports DSL connections that work with the point-to-point over ethernet protocol (PPPoE) used by most major providers. If you are not sure what protocol is used for your DSL connections, ask your provider. If you have a single-user workstation with a graphical interface, the DSL connection should be set up with the YaST modules ADSL or T-DSL.

The ppp and smpppd packages must be installed. It is best to use YaST for this purpose. Configure your network card with YaST. Do not activate dhcp. Set a fixed IP address instead, such as

The parameters set with the DSL module of YaST are saved in the file /etc/sysconfig/network/providers/provider0. In addition, there are configuration files for the smpppd (SUSE meta ppp daemon) and its front-ends kinternet and cinternet. For information, refer to man smpppd. If necessary, start the network with the command rcnetwork start and smpppd with the command rcsmpppd start.

On a system without a graphical user interface, use the commands cinternet --start and cinternet -stop to establish or terminate a connection. On a graphical user interface, this can be done with kinternet. This program is started automatically in KDE if you used YaST to set up DSL. Click the gear icon in the control panel. Select Communication/Internet+Internet Tools+kinternet. A plug icon then appears in the control panel. Start the connection by clicking the icon and terminate the connection later with another click.

25.2.2. DSL Connection by Dial-on-Demand

Dial-on-demand means that the connection is automatically set up when the user goes online, for example, when visiting a web site in a browser or when sending an e-mail. After a certain amount of idle time when no data is sent or received, the connection is automatically dropped. Because the dial-up connection via PPPoE, the protocol for ADSL, is very fast, it seems as if it were a dedicated line to the Internet.

Using dial-on-demand, however, really only makes sense if you have a flat-rate connection. If you use it but are charged for time online, make sure there are no interval processes, such as a cron job, periodically establishing a connection. This could get quite expensive.

Although a permanent online connection would also be possible using a DSL flat-rate connection, there are certain advantages to having a connection that only exists for a short amount of time when needed:

  • Most providers drop the connection after a certain period of time.

  • A permanent connection can be considered a drain on resources (e.g., IP addresses).

  • Being online permanently is a security risk, because hackers may be able to comb the system systematically for vulnerable areas. A system that is only accessible over the Internet when necessary and is always changing IP addresses is significantly more difficult to attack.

Dial-on-demand can be enabled using YaST. Alternatively, set it up manually. Set the parameter DEMAND=yes in the /etc/sysconfig/network/providers/provider0 file then define an idle time via the variable IDLETIME=60. This way, an unused connection is dropped after sixty seconds.

To set up a DSL gateway for private networks, refer to the following article from the support portal: http://portal.suse.de/sdb/en/2002/07/masq80.html.