Linux Server Hacks

A competent system administrator knows that a Linux server is a high performance system for routing large amounts of information through a network connection. Setting up and maintaining a Linux server requires understanding not only the hardware, but the ins and outs of the Linux operating system along with its supporting cast of utilities as well as layers of applications software. There's basic documentation online but there's a lot beyond the basics you have to know, and this only comes from people with hands-on, real-world experience. This kind of "know how" is what we sought to capture in Linux Server Hacks.

Linux Server Hacks is a collection of 100 industrial-strength hacks, providing tips and tools that solve practical problems for Linux system administrators. Every hack can be read in just a few minutes but will save hours of searching for the right answer. Some of the hacks are subtle, many of them are non-obvious, and all of them demonstrate the power and flexibility of a Linux system. You'll find hacks devoted to tuning the Linux kernel to make your system run more efficiently, as well as using CVS or RCS to track the revision to system files. You'll learn alternative ways to do backups, how to use system monitoring tools to track system performance and a variety of secure networking solutions. Linux Server Hacks also helps you manage large-scale Web installations running Apache, MySQL, and other open source tools that are typically part of a Linux system.

O'Reilly's new Hacks Series proudly reclaims the term "hacking" for the good guys. Hackers use their ingenuity to solve interesting problems. Rob Flickenger is an experienced system administrator, having managed the systems for O'Reilly Network for several years. (He's also into community wireless networking and he's written a book on that subject for O'Reilly.) Rob has also collected the best ideas and tools from a number of other highly skilled contributors.

Written for users who already understand the basics, Linux Server Hacks is built upon the expertise of people who really know what they're doing.

Table of Contents

How to Become a Hacker 

Preface 

Server Basics 

       1. Removing Unnecessary Services 

       2. Forgoing the Console Login 

       3. Common Boot Parameters 

       4. Creating a Persistent Daemon with init 

       5. n>&m: Swap Standard Output and Standard Error 

       6. Building Complex Command Lines 

       7. Working with Tricky Files in xargs 

       8. Immutable Files in ext2/ext3 

       9. Speeding Up Compiles 

       10. At Home in Your Shell Environment 

       11. Finding and Eliminating setuid/setgid Binaries 

       12. Make sudo Work Harder 

       13. Using a Makefile to Automate Admin Tasks 

       14. Brute Forcing Your New Domain Name 

       15. Playing Hunt the Disk Hog 

       16. Fun with /proc 

       17. Manipulating Processes Symbolically with procps 

       18. Managing System Resources per Process 

       19. Cleaning Up after Ex-Users 

       20. Eliminating Unnecessary Drivers from the Kernel 

       21. Using Large Amounts of RAM 

       22. hdparm: Fine Tune IDE Drive Parameters 

Revision Control 

       23. Getting Started with RCS 

       24. Checking Out a Previous Revision in RCS 

       25. Tracking Changes with rcs2log 

       26. Getting Started with CVS 

       27. CVS: Checking Out a Module 

       28. CVS: Updating Your Working Copy 

       29. CVS: Using Tags 

       30. CVS: Making Changes to a Module 

       31. CVS: Merging Files 

       32. CVS: Adding and Removing Files and Directories 

       33. CVS: Branching Development 

       34. CVS: Watching and Locking Files 

       35. CVS: Keeping CVS Secure 

       36. CVS: Anonymous Repositories 

Backups 

       37. Backing Up with tar over ssh 

       38. Using rsync over ssh 

       39. Archiving with Pax 

       40. Backing Up Your Boot Sector 

       41. Keeping Parts of Filesystems in sync with rsync 

       42. Automated Snapshot-Style Incremental Backups with rsync 

       43. Working with ISOs and CDR/CDRWs 

       44. Burning a CD Without Creating an ISO File 

Networking 

       45. Creating a Firewall from the Command Line of any Server 

       46. Simple IP Masquerading 

       47. iptables Tips & Tricks 

       48. Forwarding TCP Ports to Arbitrary Machines 

       49. Using Custom Chains in iptables 

       50. Tunneling: IPIP Encapsulation 

       51. Tunneling: GRE Encapsulation 

       52. Using vtun over ssh to Circumvent NAT 

       53. Automatic vtund.conf Generator 

Monitoring 

       54. Steering syslog 

       55. Watching Jobs with watch 

       56. What's Holding That Port Open? 

       57. Checking On Open Files and Sockets with lsof 

       58. Monitor System Resources with top 

       59. Constant Load Average Display in the Titlebar 

       60. Network Monitoring with ngrep 

       61. Scanning Your Own Machines with nmap 

       62. Disk Age Analysis 

       63. Cheap IP Takeover 

       64. Running ntop for Real-Time Network Stats 

       65. Monitoring Web Traffic in Real Time with httptop 

SSH 

       66. Quick Logins with ssh Client Keys 

       67. Turbo-mode ssh Logins 

       68. Using ssh-Agent Effectively 

       69. Running the ssh-Agent in a GUI 

       70. X over ssh 

       71. Forwarding Ports over ssh 

Scripting 

       72. Get Settled in Quickly with movein.sh 

       73. Global Search and Replace with Perl 

       74. Mincing Your Data into Arbitrary Chunks (in bash) 

       75. Colorized Log Analysis in Your Terminal 

Information Servers 

       76. Running BIND in a chroot Jail 

       77. Views in BIND 9 

       78. Setting Up Caching DNS with Authority for Local Domains 

       79. Distributing Server Load with Round-Robin DNS 

       80. Running Your Own Top-Level Domain 

       81. Monitoring MySQL Health with mtop 

       82. Setting Up Replication in MySQL 

       83. Restoring a Single Table from a Large MySQL Dump 

       84. MySQL Server Tuning 

       85. Using proftpd with a mysql Authentication Source 

       86. Optimizing glibc, linuxthreads, and the Kernel for a Super MySQL Server    

       87. Apache Toolbox 

       88. Display the Full Filename in Indexes 

       89. Quick Configuration Changes with IfDefine 

       90. Simplistic Ad Referral Tracking 

       91. Mimicking FTP Servers with Apache 

       92. Rotate and compress Apache Server Logs 

       93. Generating an SSL cert and Certificate Signing Request 

       94. Creating Your Own CA 

       95. Distributing Your CA to Client Browsers 

       96. Serving multiple sites with the same DocumentRoot 

       97. Delivering Content Based on the Query String Using mod_rewrite    

       98. Using mod_proxy on Apache for Speed 

       99. Distributing Load with Apache RewriteMap 

       100. Ultrahosting: Mass Web Site Hosting with Wildcards, Proxy, and Rewrite    

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