W6 Perl Program Repair Shop and Red Flags
Mark-Jason Dominus, Consultant and Author
1:30 p.m.–5:00 p.m.

Who should attend: Anyone who writes Perl programs regularly. Participants should have at least three months' experience programming in Perl.

You've probably been working too hard when you program, writing twenty lines of code when you only needed ten. But there is a better way, and I will show it to you. You'll learn how to improve your own code and the code of others, making it cleaner, more readable, more reusable, and more efficient, while at the same time making it 30-50% smaller. Smaller code contains fewer bugs and takes less time to maintain.

We will examine several real code examples in detail and see how to improve them. We'll focus on red flags--warning signs in your code that are plainly visible once you know what to look for--and on techniques that require little complex thought or ingenuity. All the bad code in this class is guaranteed 100% genuine and typical.

Participants are encouraged to submit their own code for anonymous review in the class. (Send it to mjd-lisa-2003+@plover.com.) Class content varies depending on submissions, but is sure to include some of the topics listed below.

Topics include:

• Families of variables
• Making relationships explicit
• Refactoring
• Programming by convention
• The Flesh Blanket
• Conciseness
• Why you should avoid the "." operator
• Elimination of global variables
• Superstition
• The "use strict" zombies
• Repressed subconscious urges
• The cardinal rule of computer programming
• The psychology of repeated code
• Techniques for eliminating repeated code
• What can go wrong with "if" and "else"
• The Condition That Ate Michigan
• Resisting "Holy Doctrine"
• Trying it both ways
• Structural vs. functional code
• Elimination of structure
• Boolean values
• Programs that take two steps forward and one step back
• Programs that are 10% backslashes
• 'print print print print print '
• C-style "for" loops
• Loop counter variables
• Array length variables
• Unnecessary shell calls
• How (and why) to let "undef" be the special value
• Confusion of internal and external representations of data
• Tool use
• Elimination of repeated code with higher-order functions
• Learning to use a hammer
• The "swswsw" problem
• Avoiding special cases
• Using uniform data representations

Mark-Jason Dominus (W3, W6) has been programming in Perl since 1992. He is a moderator of the comp.lang.perl.moderated newsgroup, the author of the Text::Template, Tie::File, and Memoize modules, a contributor to the Perl core, and author of the perlreftut man page. His work on the Rx regular expression debugger won the 2001 Larry Wall Award for Practical Utility. He lives in Philadelphia with his wife and several plush octopuses.

W7 Cisco Device Configuration Basics, Part 2
Steve Acheson and Laura Kuiper, Cisco Systems
1:30 p.m.–5:00 p.m.

Who should attend: Anyone who bought a Cisco router or switch on Ebay and wants to know how to configure it. This class will build on the morning class, W4, to help you get the most out of your Cisco equipment.

Topics include:

• Review of IOS capabilities and image features
• Setting up SNMP monitoring
• SSH (secure access)
• Switch specifics
  • Spanning tree
  • Trunking
  • Differences between CatOS- and IOS-based switches
• Router Specifics
  • Making your router a DHCP server
  • Doing NAT/PAT with your router
  • Using the GUI SDM (Security Device Manager) to configure your router
• More security
  • PVLAN edge (protected port)
  • Local authentication
  • RADIUS authentication
  • Advanced ACLs
  • Using your router as a VPN gateway
• Additional capabilities your router offers

Steve Acheson (M7, W4, W7, F2) is currently an Information Security Architect at Cisco Systems, Inc., where he is a senior member of the Corporate Information Security Department, responsible for network and system security, including designing internal security architecture and external/firewall access. Before working for Cisco, Steve managed security for NASA's Numerical Aerospace Simulations facility at Ames Research Center. He has worked in the field for over 15 years as a system administrator, network engineer, and security analyst.

Laura Kuiper (W4, W7, F2) is currently a Computer Security Architect at Cisco Systems, Inc., where she is a senior member of the Computer Information Security Department, responsible for network and system security, including designing internal security architecture and external/firewall access. Before working for Cisco, Laura managed the network at SAIC. She has worked in the field as a network engineer and security analyst for over 9 years.

W8 Introduction to Host Configuration and Maintenance with Cfengine
Mark Burgess, Oslo University College
1:30 p.m.–5:00 p.m.

Who should attend: System administrators with a minimal knowledge of a scripting language who wish to start using cfengine to automate the maintenance and security of their systems. UNIX administrators will be most at home in this tutorial, but cfengine can also be used on Windows 2000 and above.

Cfengine is a tool for setting up and maintaining a configuration across a network of hosts. It is sometimes called a tool for "Computer Immunology"--your computer's own immune system. You can think of cfengine as a very high level language, much higher-level than Perl or shell, together with a smart agent. The idea behind cfengine is to create a single "policy" or set of configuration files that describes the setup of every host on your network, without sacrificing their autonomy.

Cfengine runs on every host and makes sure that it is in a policy-conformant state; if necessary, any deviations from policy rules are fixed automatically. Unlike tools such as rdist, cfengine does not require hosts to open themselves to any central authority, nor to subscribe to a fixed image of files. It is a modern tool, supporting state-of-the-art encryption and IPv6 transport, that can handle distribution and customization of system resources in huge networks (tens of thousands of hosts). Cfengine runs on hundreds of thousands of computers all over the world.

Topics include:

• The components of cfengine and how they are used
• How to get the system running
• How to develop a suitable policy, step by step
• Security
• Examples
• How to customize cfengine for special tasks

Mark Burgess (W8, F4) is a professor at Oslo University College and is the author of cfengine. He has been researching the principles of network and system administration for over ten years and is the author of Principles of Network and System Administration (John Wiley & Sons). He is frequently invited to speak at conferences.