Linux Internet connection with diald

Diald is a program that sets up a SLIP interface and monitors it continuously.

When a packet is sent to the SLIP interface, diald looks at the packet and applies a set of rules set in its configuration files. On the basis of these rule, it decides whether or not to dial the ISP and establish a working connection.

The working connection can be SLIP or PPP (or indeed other protocols). This page only considers the use of PPP.

When diald decides that it has to open a connection, it dials the ISP and sets up the PPP connection; it then passes on the packet it got on the SLIP interface.

If your ISP assigns dynamic IP addresses, the first packets will get lost and will need to be sent again, because the correct IP address for the ISP is not known until after the PPP connection has been set up.

Configuration files

On Debian Linux, configuration files for diald are stored in /etc/diald and those for PPP are stored in /etc/ppp. Your own Linux distribution may expect to find these in different places: check your manual pages and look in /usr/lib and /var/lib in addition to /etc.

diald configuration

All the configuration files should be owned by the admin user and not writable by anyone except the admin user and root. Files containing ISP passwords (ppp.chat) should not be readable by anyone else, either. /etc/diald/diald.conf and /etc/diald/diald.defs are set up in the distribution and should be left alone until you really know what you are doing. These files define the rules and the definitions for diald.

The file that controls your own setup is /etc/diald/diald.options

PPP configuration

The files needed for PPP are in /etc/ppp. They are /etc/ppp/options and /etc/ppp/ppp.chat (which is the same script as is used when PPP is run without diald).

Note that PPP has a minimal configuration when it is used with diald. It is up to diald to manage the modem line.

Up to my Linux Internet connection page

Last updated on 5th May 1997 by Oliver Elphick