Debian Administration

cdpr is a nifty little command which speaks the Cisco Discovery Protocol, allowing you to learn interesting things from your network.

Finally following up on the previous article on the subject, I found some time to investigate logging what happens in an internal-sftp session using rsyslog.

In our previous brief introduction to mod_perl we showed how to install it, and how to use it to improve the performance of simple Perl-based CGI-scripts. In this conclusion we'll show how you can do more useful things with a little bit of effort.

Apache is currently the world's most popular webserver. There are many alternative webservers, but Apache was one of the first which offered real control, flexibility, and numerous available extensions. With the introduction of mod_perl you can directly control almost every aspect of your webserver with pure Perl. Read on for a brief introduction to using mod_perl.

The readline library is used by many programs which need to provide a pleasant environment for performing text entry, offering completion, history, and advanced editing facilities. There are applications which, for various reasons, do not use it, but this is something that may be fixed with the addition of the rlwrap readline wrapper.

When changing software configuration it is always a good idea to test things as thoroughly as you can. In the case of SMTP it is generally possible to test things offline pretty easily, and then perform simple tests via a manual telnet - but the SWAKS tool makes SMTP-testing even simpler.

Configuring a firewall policy using iptables can be difficult. If you do it by hand, you need to learn a complicated command line syntax and understand packet flow inside Linux kernel very well. GUI applications such as Firestarter can help build simple configuration but quickly run out of steam when security policy becomes complex. This article introduces "Firewall Builder", a GUI firewall configuration and management tool designed to help solve this problem.

I tried several times to get SMTP authentication working for use in a modern environment with much wailing and gnashing of teeth. For starters, I don't want to have to authenticate every client on my LAN. Clients coming from my home subnet should be trusted by IP and should not have to authenticate. Secondly, I want to be able to relay mail from any client if that client authenticates via TLS from anywhere on the internet. Hopefully this will save other people some time and sanity.

Handling mostly old or problematic hardware and not always having a stable internet connection, I have been struggling to find a live-cd/usb-key system which is slim, easy and fast to customize, fully encryptable and includes the debian network installer.

In the quest for the fastest boot ever (see Booting Debian in 14 seconds), you may want to consider setting the variable CONCURRENCY=shell in /etc/default/rcS, recalling from your your theoretical studies that "Parallel is faster than Sequential."