DSL HOWTO for Linux Hal Burgiss [email protected] Original Author: David Fannin Edited by Greg LeBlanc v1.71, 2002−07−21 Revision History Revision v1.71 2002−07−21 Revised by: hb Add another supported modem only. Revision v1.7 2002−07−14 Revised by: hb More small updates. Revision v1.6 2002−05−23 Revised by: hb Various small updates. Revision v0.92 1999−04−10 Revised by: df First release (ADSL mini HOWTO). This document examines the DSL family of high speed Internet services now being deployed in various markets worldwide. Information is included on the technology behind DSL as well as subscribing, installing, configuring, and troubleshooting, with an emphasis on how this impacts Linux users. DSL HOWTO for Linux Table of Contents 1. Introduction.....................................................................................................................................................1 1.1. Document Structure and Reading Guidelines...................................................................................1 1.2. What's New.......................................................................................................................................2 1.3. Copyright..........................................................................................................................................3 1.4. Credits...............................................................................................................................................3 1.5. Disclaimer.........................................................................................................................................4 1.6. Feedback...........................................................................................................................................4 1.7. Conventions, Usage and Terminology..............................................................................................4 2. Installation.......................................................................................................................................................7 2.1. Pre−Installation.................................................................................................................................7 2.2. Installation Options −− Self Install or Not........................................................................................8 2.3. Wiring/Installation Options..............................................................................................................8 Figure 1: DSL Block Diagram with Splitter (NID not shown)..................................................9 Figure 2: DSL Splitterless (a.k.a. filtered) Block Diagram.......................................................9 2.4. Self Install − Wiring.......................................................................................................................10 2.4.1. The Homerun..................................................................................................................10 2.5. Wire the Splitter..............................................................................................................................11 2.6. Wire the DSL Jack..........................................................................................................................11 Figure 3: RJ11 Wiring options ................................................................................................12 2.7. Installing Microfilters.....................................................................................................................12 2.8. Installing an Ethernet Modem.........................................................................................................12 2.8.1. Installing the Ethernet Network Card (NIC)...................................................................13 2.9. Installing a USB Modem................................................................................................................13 3. Configuring Linux........................................................................................................................................15 3.1. Bridged vs PPPoX Networks..........................................................................................................15 3.1.1. Bridged/DHCP................................................................................................................16 3.1.2. PPPoX.............................................................................................................................16 3.1.3. ATM................................................................................................................................16 3.2. Configuring the WAN Interface.....................................................................................................17 3.2.1. Static IP Configuration...................................................................................................17 3.2.2. Bridged/DHCP Configuration........................................................................................17 3.2.3. PPPoE Configuration......................................................................................................18 3.2.4. PPPoA.............................................................................................................................20 3.2.5. PPTP/PPPoA with Alcatel Ethernet Modems................................................................20 3.2.6. Modem/Router Configuration.........................................................................................21 3.3. Connect...........................................................................................................................................23 4. Securing Your Connection...........................................................................................................................24 4.1. Security Quick−start.......................................................................................................................24 5. Performance Tuning and Troubleshooting................................................................................................26 5.1. Tuning.............................................................................................................................................26 5.1.1. TCP Receive Window....................................................................................................26 5.1.2. Interleaving.....................................................................................................................28 5.1.3. TCP Bottlenecks.............................................................................................................28 5.1.4. Dropped PPP Connections..............................................................................................29 i DSL HOWTO for Linux Table of Contents 5.2. Installation Problems......................................................................................................................29 5.2.1. No sync...........................................................................................................................29 5.2.2. Network Card (NIC) Problems.......................................................................................30 5.2.3. IP Connection Problems.................................................................................................30 5.3. Sync Problems................................................................................................................................31 5.4. Network and Throughput Problems................................................................................................32 5.4.1. Miscellaneous Network Problems..................................................................................35 5.5. Measuring Throughput....................................................................................................................36 6. Appendix: DSL Overview............................................................................................................................38 6.1. The DSL Family.............................................................................................................................38 ADSL........................................................................................................................................38 G.Lite........................................................................................................................................39 SDSL.........................................................................................................................................39 IDSL..........................................................................................................................................39 RADSL.....................................................................................................................................39 HDSL........................................................................................................................................40 VDSL........................................................................................................................................40 UDSL........................................................................................................................................40 G.SHDSL..................................................................................................................................40