Focus on Software

by David A. Bandel

The time is on us once again. The “feature freeze” for 2.3 was just announced. By the time you read this, it will be down to last-minute testing and making sure all is well before final release. What's new other than more device drivers? I don't yet know everything new, but I do know that once again, I'll need to learn new firewalling software. For 2.0, it was ipfwadm--not bad, but no fine-grained control. For 2.2, it is ipchains--I liked the control, but heard many complaints about its complexity, and I found very few configuration tools for this beast. So I'm off to download and compile the latest kernel to test the new netfilter that will be 2.4's packet mangling software. Here's hoping for configurability and simplicity in one package.


This aptly named software is, you guessed it, a firewall configuration program. Basically, mason learns about the traffic passing through your gateway (soon to be your firewall) and records the traffic so you can build a firewall brick by brick (or chain by chain, as it were). The recording is done in the form of a line that can be used by mason or by the ipchains-restore script. When the software fires up, it checks what type of system you have: if it is a 2.0.x system, it will use ipfwadm; if 2.2.x, it will use ipchains. The new netfilter software rules should not be significantly different from ipchains, and support will be added before the 2.4.x release if it hasn't been already (some of the code was in place but disabled in the version I tested). The software does require you to review the rules, so you do need to be able to read and understand them to decide which rules to keep. It requires bash, ipchains or ipfwadm, and a kernel built with firewall support.


This command-line system information utility will fill pages. si will tell most folk more than they ever cared to know about their system, what resources (IRQs, DMAs, etc.) are being used, what programs are running, how much memory they're using, etc. The information can be obtained by other programs, but it will take a few. In fact, I'm not sure what more information you could get or want. While I haven't verified it, I suspect this program is reading a good part of the /proc tree to return all this information; at least, it matches the information I know to be available, just not as easily readable in /proc. It requires glibc.


Going from information overload to almost underwhelming by comparison, this utility will provide one page of information nicely formatted in HTML—great for putting something up on a web page. I looked, and while it had a fair amount of information for only one page's worth, it was innocuous enough. I would feel safe putting this on a public web page, whereas the utility above is more information than even a wannabe cracker would want (or need). It requires Perl.

DNS sleuth:

This little jewel is a DNS checker. With both a command-line interface and a web interface, sleuth will check whether the configuration of your DNS complies with the RFCs. It will give you warnings for some things and errors when it sees something completely wrong. The best part is it will tell you what is wrong and reference the RFC so you can see for yourself why it's bad and how to fix it. No more guessing if it's correct or not—fast and thorough. It requires Perl and the Net::DNS Perl module.


Have a large LAN? Thankfully, I don't any more. But if I did, particularly one that spans buildings (much less floors), and typically two or more /24 (class C) networks, I'd be using something like this database to keep it sorted. It really is overkill for a small network, though. I think I'd add a few comment fields to hold a name and number or two for problems. Makes a nice complement to a resource manager like MOT (Ministry of Truth) or IRM (IT Resource Manager). It requires Perl, CGI, DBI, DBD modules, MySQL and a web server.


yafc is yet another FTP client. You may be thinking, “I already have both graphical and command-line FTP tools, and ncftp (a command-line client to which this is a competitor) fills the latter niche nicely.” However, the nice thing about competition is the newcomer has to have something that works better than the incumbent, or otherwise why bother? Well, this one has—at least for me. Side by side, I found yafc easier to use (important even to a command-line-junkie like myself) and better designed. It has a few parameters you can set, like cache and others. It requires libncurses, libreadline and glibc.


It's been a while since I looked at any kind of HTML markup editor, and I don't remember them being all that friendly or easy to use, so my HTML editor of choice has always been vi. Now, you've probably guessed I'm not much of a webmaster (it's true, I'm not)--I'm into substance over form. About the only thing I didn't see in august, but would like to, is some markup selections for PHP. It requires Tcl/Tk.

David A. Bandel ( is a Linux/UNIX consultant currently living in the Republic of Panama. Co-author of Que Special Edition: Using Caldera OpenLinux, he plans to spend more time writing about Linux while relaxing and enjoying life in the “Crossroads of the World”.
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