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Supporting ADSL technology under OpenBSD

Introduction and disclaimer

This page deals with setting up and using ADSL connections under OpenBSD. It is the result of some personal experience in this area, discussions with other people, and information found on the Internet. If you feel something is incorrect, or if you think you have useful information which should be on this page, feel free to drop me a note.

Also, I cannot be held responsible for direct or indirect damage or any other consequence of using, or not using, or using incorrectly, the information contained on this page. Further, I also cannot be held responsible for the content on pages I link to.

Problem description

In order to use a typical ADSL connection, two problems need to be solved. First of all, you need to have some sort of ADSL modem, to perform the physical signal modulation and line handling. Secondly, usually some form of authentication will be needed in order to use the connection, and you will need to have software capable of performing this authentication on your platform.

ADSL Modems

The problem with different ADSL modems is whether or not you need a specific software driver on your platform in order to be able to use the modem, and whether or not such a driver exists for OpenBSD.

Ethernet bridges

Ethernet-bridging modems are a first type of ADSL modem. These modems are external modems, that bridge an ethernet connection over an ADSL line. In other words, all you have to do is connect your machine or network via the ethernet connection to the modem, and plug the ADSL line into the modem. The advantage is that no specialized driver is needed for this type of modem, so in principle all modems in the class should be usable with OpenBSD.

Routers, DSL firewalls, and related devices

These devices act as non-transparent gateways for your network or machine. Simply plug your network into the device via an ethernet interface, and the device handles all the other details. Since no driver is needed, they are also fully compatible with OpenBSD. Beware though, that the device must be able to interface with the chosen authentication method of your ADSL provider (e.g. if your ADSL provider requires you to use PPTP for authentication purposes, the device you purchase must be able to use this method).

USB modems

This type of modem connects via USB to your machine. In other words, you do not need a separate network card to connect to this type of modem. The downside, however, is that you need a software driver compatible with your operating system for this type of modem.

PCI modems

(under construction)

Authentication

(under construction)

Specific ADSL providers

Other links