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This roundup which sort of encapsulates the first half of December and most of November is not an easy one. My friends have had terrible losses and I lost a friend - that said - one thing I do know about my friends is that they do not want systhread to stop doing what systhread does... so here goes - visit the link to see some info about my friend, we got autobuilds for the systhread repo to work (yaaay), we are looking into building a mini vmware cluster (do read the post for you ESX dudes) and last and certainly not least the bloody site audit is done.

There are many a diagnostic program/system/framework/architecture out there to help the systems administrator/programmer/network administrator along with their day to day lives. Ultimately almost all of the good pieces of software that exist allow for easy interaction: that is send back a signal and/or a message. The problem: writing the original diagnostic scripts to begin with. In this text a look at writing shell scripts to check on conditions from many points of view - that is from the perspective of local checks only versus remotely executing checks using secure shell.

The pre-release of netward - a simple packet watcher - has been released. Netward monitors for repeated scans that might be break in scans. Not a drop in replacement for a full blown Intrusion Detection System (IDS) netward compliments such systems or acts as a great tool for watching scans on a host. Additionally netward is good for low priority systems (or internal) where the threat level is neglible. Last and not least the true purpose is to expose leveraging libpcap and how it cane be used to save your network.

In the first part of the libpcap series a rudimentry packet reader (or sniffer) was built which could read and print tcp/ip traffic on a particular interface. In the second text a look at some simple checks of the data itself, adding options like interface selection, libpcap filter options and verbosity levels. Some of the checks included are:

• IP Packet Truncation
• IP Header Length
• Ethernet Header Length

The filter options are eventually passed exactly like tcpdump using the tcpdump argv vector copy.

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Reading network data can be difficult. Tools and utilities such as wireshark, tcpdump and nmap exist that can aide in dealing with networks at multiple levels. What if, however, one needed to integrate packet reading or writing into their own code? The libpcap library exists for the very purpose of dealing with network data a higher level than the raw socket API. In part one of a three part series a look at writing a very simplistic packet reader utility which can easily be used as the basis for integrating the functionality of libpcap into an existing application.

Open Source software is not just and idea, it is also a way of doing things. The usual method of Open Source software management are familar once dissected. In the second (and likely last) installment of the Facets of Open Source series; a look at how software collaboration is often managed and three real world examples displaying the leveraging power of Open Source.

A long time ago in net time (so around 1999) I wrote an article about setting up DNS. The article I wrote was terse to say the least. Recently I had the opportunity to work on a new DNS installation that grew to become somewhat complex. I decided to do a series on DNS covering the scope of what I have dealt with in hopes that it might help others. Although the scope I have dealt with is really mild; we have to start somewhere. In this first part of the series - an extremely simple DNS server with very few hosts is covered to get the feet wet.

Sometimes getting a grasp on what Open Source is and how it can be leveraged is difficult. There are many facets of Open Source, however, the two most interesting points of Open Source are: Direct cost savings from Open Source software. Slight difference in support models. In part one of the series, a generalized look at the costs and savings of Open Source. Story.

The traditional Unix utility uses options and arguments to parse command line parms that dictate how the utility should work. Long options is one way to make a utility's usage somewhat natural; for example: util --version. Some utilities use keywords and command/sub-command syntax. It is possible to combine the two without causing too much confusion.

The enlightenment window manager has gone from pushing the limits on graphics to a now all encompassing e environment with supporting libaraies, APIs of all sorts, and a rapidly growing feature rich window manager in e17.

There are two updates for the beginning of the month. The nettest suite and etu programs have received enough changes to warrant full releases. Nettest has branched and released to 2.2 with make cleanups, code cleanups and more greater (and likely unfullfilled) plans. The etu utility now supports non jpeg formats in a very proper way: I would argue that it is perfect.

Sometimes even the simplest of programs/scripts can run across what the author thinks would be a walk in the park. After taking a long (and often sobering) look at what an enhancement (I refuse to call it a feature ... ) would take; the first reaction might be BEGIN: backpedal. A longer (and again - sober) look often reveals that the answer may in fact already exist and just to add insult to injury you have used it before. In the following text an example of an extremely simple program's journey to figure out what is the best and easiest method to add an enhancement (not a feature...)

Not exactly the clearest of titles... recently I had to setup and configure several subvesion servers that use webdav for authentication. Setting up the authentication and repositories for a single repository is pretty straightforward. If many repositories need to be created and maintained that are completely seperate, then a script (or set of scripts) definitely makes life easier. In the text below, just such a scenario cropped up and my first pass at working a script.

Ever had ip_conntrack_max overrun and started losing not just valid packets but possibly valid data? The solution, script it. Try using your favorite scripting languages to tackle a relatively simple problem. In the example provided, a first draft (which works) is cranked out to stem future overruns . . . then a second draft to fix those Oi I was in a hurry problems.

One of theneat things a user can do on Unix is play around with the Bourne Again Shell (bash). An even more interesting thing is how the environment can be tweaked to a particular user's preference. In this text a look at how the Bash prompt can be manipulated by inserting commands and even shell code functions directly into the prompt itself.

Despite the lack of new texts and apparent lack of updated code a lot has been going on here at systhread. Code has been receiving tweaks on a seemingly regular basis (small tweaks about once/week on several utilties). The site was redesigned - but those who pay close attention will realize the only thing that changed was the navigation scheme. The layout is nearly identical to past incarnations. Also tossed in are a few notes on what will be going on over the next couple of months.

I was originally going to call it parse this but thought better of it. Deciding upon and implementing command line options, arguments and flags can be a real bear. There exist a lot of tools to help out programmers, although some of them may be a bit heavy handed; solution - roll your own when possible. In this text a look at short and long opt parsing options with limited examples. I would have gone more in depth, however, the possibilities are so endless (especially in shellcode and Perl) that I chose some small examples.

Bourne Again Shell offers a lot of power, flexiblity and fun. Many new Unix users do not realize the flexibility of the shell environment; indeed; many new Unix users regard the shell as primitive and too restricted: nothing could be further from the truth. With very little time investment a new Unix user can learn how not to just make their work environment in the shell more productive but even a little fun.

The nullfs filesystem is a passthrough filesystem. When nullfs is mounted it - literally copies the filesystem transaction. If a file is deleted, nullfs simply transmits the information down to the lower filesystem. Conversely, if a file is created, it does the same and tacks on all of the data needed for the filesystem underneath. Why is that a good thing? Where did nullfs come from and why?. What else, if anything, is it good for? The series focuses on where nullfs comes from, how it can be leveraged, a code walk and a skeloten implementation (nearly a blind copy).

Many projects require different languages as either separate or integral parts of the overall project impetus. Indeed some coding projects have code that generates code for other parts of the projects. Most common among such tools is using lexical builders to create code to be compiled. In this text an example project that uses several different languages for it's components and the problems that can crop up with using several different languages in one project.