Table of Contents Preface .......................................................... 1 Who this book is for ................................................ 2 Versions ........................................................ 2 Organization ...................................... ............... 3 Conventions used in this book ......................................... 4 Differences between the first edition and second edition ...................... 5 Comments and questions ............................................ 5 Hal's acknowledgments from the first edition .............................. 6 Acknowledgments for the second edition ................................. 6 1. Networking Fundamentals ......................................... 9 1.1 Networking overview ............................................ 9 1.2 Physical and data link layers ...................................... 11 1.3 Network layer ................................................ 12 1.4 Transport layer ................................................ 18 1.5 The session and presentation layers ................................. 19 2. Introduction to Directory Services ................................... 24 2.1 Purpose of directory services ...................................... 24 2.2 Brief survey of common directory services ............................ 25 2.3 Name service switch ............................................ 29 2.4 Which directory service to use ..................................... 29 3. Network Information Service Operation .............................. 31 3.1 Masters, slaves, and clients ....................................... 31 3.2 Basics of NIS management ....................................... 34 3.3 Files managed under NIS ........................................ 41 3.4 Trace of a key match ............................................ 52 4. System Management Using NIS ..................................... 56 4.1 NIS network design ............................................ 56 4.2 Managing map files ............................................ 58 4.3 Advanced NIS server administration ................................ 65 4.4 Managing multiple domains ...................................... 67 5. Living with Multiple Directory Servers ............................... 70 5.1 Domain name servers ........................................... 70 5.2 Implementation ............................................... 72 5.3 Fully qualified and unqualified hostnames ............................ 74 5.4 Centralized versus distributed management ........................... 76 5.5 Migrating from NIS to DNS for host naming .......................... 77 5.6 What next? ................................................... 77 6. System Administration Using the Network File System ................... 78 6.1 Setting up NFS ................................................ 79 6.2 Exporting filesystems ........................................... 80 6.3 Mounting filesystems ........................................... 85 6.4 Symbolic links ................................................ 96 6.5 Replication .................................................. 99 6.6 Naming schemes ............................................. 103 7. Network File System Design and Operation .......................... 108 7.1 Virtual filesystems and virtual nodes ............................... 108 7.2 NFS protocol and implementation ................................. 109 7.3 NFS components ............................................. 117 7.4 Caching .................................................... 122 7.5 File locking ................................................. 127 7.6 NFS futures ................................................. 129 8. Diskless Clients ................................................ 132 8.1 NFS support for diskless clients ................................... 132 8.2 Setting up a diskless client ...................................... 133 8.3 Diskless client boot process ...................................... 136 8.4 Managing client swap space ..................................... 140 8.5 Changing a client's name ........................................ 142 8.6 Troubleshooting .............................................. 143 8.7 Configuration options .......................................... 147 8.8 Brief introduction to JumpStart administration ........................ 150 8.9 Client/server ratios ............................................ 151 9. The Automounter .............................................. 153 9.1 Automounter maps ............................................ 154 9.2 Invocation and the master map ................................... 162 9.3 Integration with NIS ........................................... 167 9.4 Key and variable substitutions .................................... 169 9.5 Advanced map tricks .......................................... 173 9.6 Side effects ................................................. 182 10. PC/NFS Clients ............................................... 184 10.1 PC/NFS today .............................................. 184 10.2 Limitations of PC/NFS ........................................ 185 10.3 Configuring PC/NFS .......................................... 188 10.4 Common PC/NFS usage issues .................................. 189 10.5 Printer services .............................................. 191 11. File Locking ................................................. 192 11.1 What is file locking? .......................................... 192 11.2 NFS and file locking .......................................... 194 11.3 Troubleshooting locking problems ................................ 196 12. Network Security .............................................. 200 12.1 User-oriented network security .................................. 200 12.2 How secure are NIS and NFS? ................................... 206 12.3 Password and NIS security ..................................... 207 12.4 NFS security ............................................... 210 12.5 Stronger security for NFS ...................................... 223 12.6 Viruses ................................................... 245 13. Network Diagnostic and Administrative Tools ........................ 247 13.1 Broadcast addresses .......................................... 248 13.2 MAC and IP layer tools ........................................ 250 13.3 Remote procedure call tools ..................................... 268 13.4 NIS tools .................................................. 276 13.5 Network analyzers ........................................... 283 14. NFS Diagnostic Tools .......................................... 295 14.1 NFS administration tools ....................................... 295 14.2 NFS statistics ............................................... 298 14.3 snoop ..................................................... 307 14.4 Publicly available diagnostics ................................... 311 14.5 Version 2 and Version 3 differences ............................... 317 14.6 NFS server logging ........................................... 318 14.7 Time synchronization ......................................... 331 15. Debugging Network Problems .................................... 335 15.1 Duplicate ARP replies ......................................... 335 15.2 Renegade NIS server ......................................... 337 15.3 Boot parameter confusion ...................................... 338 15.4 Incorrect directory content caching ............................... 339 15.5 Incorrect mount point permissions ................................ 343 15.6 Asynchronous NFS error messages ............................... 345 16. Server-Side Performance Tuning ................................. 349 16.1 Characterization of NFS behavior ................................ 349 16.2 Measuring performance ........................................ 351 16.3 Benchmarking .............................................. 352 16.4 Identifying NFS performance bottlenecks ........................... 353 16.5 Server tuning ............................................... 357 17. Network Performance Analysis ................................... 367 17.1 Network congestion and network interfaces ......................... 367 17.2 Network partitioning hardware .................................. 369 17.3 Network infrastructure ........................................ 371 17.4 Impact of partitioning ......................................... 372 17.5 Protocol filtering ............................................ 374 18. Client-Side Performance Tuning .................................. 376 18.1 Slow server compensation ...................................... 376 18.2 Soft mount issues ............................................ 381 18.3 Adjusting for network reliability problems .......................... 382 18.4 NFS over wide-area networks ................................... 384 18.5 NFS async thread tuning ....................................... 385 18.6 Attribute caching ............................................ 387 18.7 Mount point constructions ...................................... 388 18.8 Stale filehandles ............................................. 390 A. IP Packet Routing ............................................. 392 A.1 Routers and their routing tables ................................... 392 A.2 Static routing ................................................ 396 B. NFS Problem Diagnosis ......................................... 397