Apache - The most popular web server on the internet, by far, modular in structure with detailed logging and diagnostics available to the administrator.
CGI scripts - Common Gateway Interface, or system scripting language for use in web servers. This technique is less efficient than scripting languages like php which are interpreted by the web server itself, but still a good way to run applications written in compiled languages (C, Fortran) from a web server. CGI scripts generally are installed in a special subdirectory cgi-bin.
Perl scripts - a dynamic programming language commonly used for web pages and system administration. Perl cannot be imbedded in html, but it does not require any extensions to the client because it runs on the server. Perl is composed of hundreds of different language elements, modules, that can be independently installed on a server.
PHP - a scripting language typically used to create dynamic web pages. PHP scripts are typically imbedded in HTML and produce standard HTML output, after processing by the server. This means that they work well with all web clients.
HTTPS site - Hyper Text Transfer Protocol (secure version) a website which serves encrypted pages, typically using port 443. HTTPS servers require certificates, which can be self-signed or purchased from a web services company. ColoradoLinux servers with pre-installed https sites have self-signed certificates.
webalizer - a simple web log analyzer which classifies traffic on a server by content, client, time, and referring pages. It also lets you see which search strings were most popular.
mysql - the leading open-source database server. It is frequently used with Apache web applications and supports important web sites such as Wikipedia and YouTube.
Sendmail - The most popular mail transport agent on the internet, very flexible, mature software with excellent logging and error reporting capabilities. It is used to accept mail on a server and delivers to local mail files, which are then read by a variety of mail clients and services.
greymilter - an effective spam filter which requires that unknown mail servers re-transmit their messages after a short delay, typically 15 minutes. All popular mail servers can recognize the error codes properly, and re-transmit their messages, but most spammers and viruses do not. After a given mail server, sender and recipient has passed the filter, additional messages sent within a week will be accepted without delay. The filter can be customized to accept all messages from certain servers or senders immediately and without filtering.
spamassassin - a spam tagging program that uses characteristics of the content and email headers to identify spam. Spamassassin comes with a large database of spam characteristics, to reliably identify spam, but it also can be customized by the system administrator and by individual users.
clamav - a free antivirus toolkit used to identify viruses, frequently updated, and capable of filtering email arriving and being sent from a mail server, as well as scanning the disk for viruses that could have arrived through other means. This software is most useful when used in combination with Windows clients, that could become infected by viruses.
IMAPs server - Internet Message Access Protocol (secure version), typically using port 993. IMAP mail servers permit their mail clients to organize email in folders that stay on the server. Most modern clients support IMAP and IMAPs. IMAPs is recommended over IMAP because it prevents hostile observers on the network from capturing usernames and passwords.
POPs server - Post Office Protocol (secure version), typically using port 995. This is the simpler of the two primary types of mail servers. POP supports only one mailbox. It is faster over narrow band connections than IMAP and works better with some mail clients.
APOP server - Post Office Protocol using port 110 but with encrypted passwords. This version isn't as commonly used as POPs.
squirrelmail - a web application written in PHP which is an IMAP client and typically runs on a HTTPs website, so the usernames and passwords are encrypted. It has the advantage that the client is an ordinary browser, and private email messages are generally not kept on it. It's probably the safest way to read email from an internet cafe or library. Squirrelmail is more customizable than most webmail applications because it has many modules that can be installed.
pine - an old-fashioned text based email client run from the command line of an ssh session or on the console. It can be remarkably efficient, especially for users already familiar with it, and it takes very few resources. Normally pine reads email directly from the files which sendmail writes, but it also can get mail off remote POP or IMAP servers.
elm - ELectronic Mail client, text-based and older than pine. Elm is so old that it isn't a part of Debian, but we include it as a courtesy to older users.
Samba - a free implementation of the SMB/CIFS networking protocol, which is how Windows machines share files and printers. A linux server with Samba installed can join a Windows domain and be a file server for Windows clients.
NFS - Networked File System services, needed to share files between unix machines. Although NFS can be very convenient, it can also slow down servers and depends on a very fast network between NFS clients and NFS servers, which need not be running the same unix variant.
FTP - File Transfer Protocol, which is used to upload and download files, especially large ones. Some web development software expects to publish files via FTP, although it isn't a secure protocol. FTP is much more secure when it is limited to anonymous FTP downloads.
CUPS - Common Unix Printing System, a full-featured print service including local and remote printers and print clients and with support for many different printer types. It has a web interface for administration.
lpd - Line Printer Daemon or Berkeley printing system provides printing services in a less elaborate manner than CUPS. It is more compact and may be somewhat more robust as well, but it lacks built-in support for most printers that do not directly interpret PostScript.
amanda - Advanced Maryland Automatic Network Disk Archiver is intelligent and flexible client-server backup software that can backup to tape or disk. It is cross-platform, robust, and moderately secure.
iptables - Standard Linux firewall software, used to block all connections to a server that are not explicitly enabled. It makes the installation of other services more complicated, but also significantly more secure.
logwatch - A log analysis tool that can be configured to notify the system administrator of relevant activity on a system in the form of a fairly compact daily email. Logwatch helps you keep track of your system, and the attacks against it.
tripwire - A package that checks system files against an encrypted database and notifies the administrator via email each day if there are differences. It is an essential tool for detecting successful attacks, the ones that require immediate action.
C compiler - A computer program that converts C source code into executable that can be run. The language C is especially important for system software. The Linux kernel and all device drivers are written in C. Most of the unix and linux operating systems are written in C. The most useful compiler for system administration, even if you are not a programmer.
C++ - A more modern version of C which supports object oriented programming and classes of data objects.
Fortran - A programming language typically used by scientists and engineers. Fortran source code files typically have the extension .f or .f77. Fortran is more numerically efficient than C, but lacking in memory management functionality.
Fortran 95 - A more modern version of Fortran, with better memory management functionality and object oriented functionality similar to C++. Free Fortran 95 compilers have not been available for long, and are not fully debugged
gdb - The GNU debugger, used with all the free compilers. In its basic form it isn't very user friendly.
gnuplot - A software package that makes plots in a variety of graphical formats. It is script-based and quite flexible.
octave - A interpreted language (no compilation needed) which is used for numerical computations and supports matrix operations. It is similar to Mathematica.
R - A programming language used for statistical analysis similar to S, object oriented, extensible, and capable of producing graphical output. More than 1000 specialized libraries are freely available for R.
Maxima - A computer algebra system used to manipulate equations and perform some computations.
Firefox - A popular and modern web browser, distributed by the Mozilla foundation, and based on Netscape.
Iceweasel - In Etch, Firefox has been renamed Iceweasel, due to some copyright restrictions. Apart from the logos, Iceweasel is very much like the most recent Firefox.
Konquerer - A web browser that was developed as a part of the KDE suite of desktop applications. It can be run under other window managers.
Ordering custom hardware - You can select some hardware that you would like us to install linux on, and ship it to Colorado Linux Systems, 2525 Arapahoe, Suite E4-114, Boulder, CO 80302, and we will work with it. We do not promise to get all devices working, since there are a few video cards and other devices that have no linux drivers. If in doubt, please ask.
Old PC - one of the best ways to explore linux is to give us an old personal computer to work with. Suprisingly old machines are capable of running linux.
DHCP - Dynamic Host Configuration Protocol is the standard way computers are dynamically assigned IP addresses. It is often used for workstations, but almost never for servers.
A router is a machine that connects more than one subnet, routing packets between two interfaces. One type of router is a ppp server, which translates packets from a serial line (typically a modem) to some other kind of internet connection.
OpenOffice is based on Star Office, quite a full featured office productivity suite which can read many of the file formats produced by Microsoft Office. It has a word processor, spreadsheet and presentation software.
KOffice is another office application suite, this one designed to run with the KDE desktop. It includes a word processor, spreadsheet, presentation package, flowcharter, project management tool, formula editor, etc.
gnumeric a simple stand-alone spreadsheet that can read a variety of other spreadsheet formats.
abiword a free stand-alone word processor that can read Word files
LaTeX is a remarkably powerful markup language which can be used to write books, papers and theses. It is very good a producing correctly formatted mathematical formulae.
The Gimp is the GNU Image Manipulation Program, which can be used to alter photographs and create new art. It supports plug-ins for and can animate images, among other things.