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First Steps with Scalix Admin Console and Scalix Web Access
1 month, 1 week ago
This article deals with the Scalix Administration Console (SAC). This web interface is the central point of administration for the Scalix server. User, group, and resource management are done here as well as controlling services and settings. In this article by Markus Feilner, we will take a short tour through the interface, add a first user, and have a closer look at the configuration options available for him/her. Towards the end, we will test the account by logging into the web client, and sending (and receiving) emails. -
Sshpass: non-interactive SSH password authentication
2 months, 2 weeks ago
SSH’s (secure shell) most common authentication mode is called “interactive keyboard password authentication”, so called both because it is typically done via keyboard, and because OpenSSH takes active measures to make sure that the password is, indeed, typed interactively by the keyboard.Sometimes, however, it is necessary to fool SSH into accepting an interactive password non-interactively. This is where sshpass comes in ....
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Pash - cross platform PowerShell is out in the wild! Announcement.
3 months, 1 week ago
PowerShell open source reimplementation for “others” (Mac, Linux, Solaris, etc…) and Windows (including Windows Mobile and Windows CE) -
Linux users answer the call: Ubuntu wireless-adapter glitch resolved
6 months, 1 week ago
"The sage advice of Linux community members gets my Linksys wireless adapter working in Ubuntu 7.10 in just a few minutes." -
The perfect server - Ubuntu Gutsy Gibbon
9 months ago
This tutorial shows how to set up a Ubuntu Gutsy Gibbon (Ubuntu 7.10) based server that offers all services needed by ISPs and hosters: Apache web server (SSL-capable), Postfix mail server with SMTP-AUTH and TLS, BIND DNS server, Proftpd FTP server, MySQL server, Courier POP3/IMAP, Quota, Firewall, etc. This tutorial is written for the 32-bit version of Ubuntu Gutsy Gibbon, but should apply to the 64-bit version with very little modifications as well. -
Microsoft responsible for nearly half of IT jobs
9 months ago
A study sponsored by the software giant found global IT spending will top $1.24 trillion in 2007, thanks in large part to itself .... -
Disk based backups with Amanda on Debian Etch
10 months ago
"This document describes how to set up Amanda (The Advanced Maryland Automatic Network Disk Archiver) on Debian Etch ... The resulting system provides a flexible backup system with many features. It will be able to back up multiple hosts via network to various devices. I chose the disk based backup for this howto .... " -
Central Log Management System
10 months, 2 weeks ago
"Central Log Management System is a simple web based logging system which allows logging all syslog messages from various Network Devices, Unix, Linux, Solaris and Windows Servers. This allows the visibility of logs from all these devices in one single interface ...." -
The perfect start with Smoothwall Express 3.0
10 months, 2 weeks ago
"Smoothwall Express is an internet firewall, which allows you to protect your network, as well as providing NAT functionality. It is ease to use and configurable via a web-based GUI. This open source firewall distribution requires absolutely no knowledge of Linux to install or use .... " -
Chrooted SSH/SFTP tutorial for Debian Etch
10 months, 2 weeks ago
"This tutorial describes two ways how to give users chrooted SSH access..." -
Preventing domain expiration
10 months, 2 weeks ago
Internet users have an equally pervasive -- and oddly similar -- problem: accidental Internet domain expiration. Your Linux user group or other nonprofit group (or, hey, even your company) is relying on some vaguely defined chain of command to make sure the domain keeps getting renewed, making the assumption everything's fine as long as no disaster has yet happened (which tactic is called "management by exception" in business school -- usually just before they cue the ominous music). Somebody drops the ball, the domain everyone's relying on expires when nobody's looking, and when the dust settles you find that a domain squatter's grabbed it. Yes, there are companies that make domain snatching their core business. They do well at it, too. Too well for my taste. -
Configure local and remote system logging
11 months, 2 weeks ago
"A Linux machine has a logging system which keeps track of what everything is doing. Anytime you authorize with sudo it gets logged. Anytime you (or someone else) connects via ssh it gets logged. Apache logs connections, mail servers log emails sent and refused. Pretty much everything keeps a log of what it is doing so you can later troubleshoot it or simply have a record of it.For those that are security minded it may not be a bad idea to keep duplicate of your logs by sending them not only to the local machine but to a remote machine as well .... " -
The most useful command line tools?
1 year ago
E. Stride writes "Our readers and experts helped us create our first guide to the 50 most-used Linux command line tools. This wildly popular guide needs updating, so we asked our inner circle to pitch in again. We're looking for the most important-most used tools for the command line." -
Entering a safe mirror when logging in with unionfs and chroot
1 year ago
"This environment is a exact copy (mirror) of the system you're working on. Because you're in safe copy of the real system, you can do whatever you like, it will never change the system, everything stays inside the cache (the readwrite branch) ... " -
A Discussion on Grub Security
1 year ago
"Today’s post isn’t so much a tutorial but more of a discussion or educational topic on grub. It was inspired by the original post here and continued discussion in the comments. I thought I would outline some suggestions on securing the grub boot loader and why Ubuntu adding a “rescue mode” entry in grub is not a security flaw and is really not any less secure than any other distribution ... " - More News
Linux.com : System Administration
Jump start your Web app deployment with a JumpBox
Software installation, deployment, and configuration can be a headache and a time sink for systems administrators. To ease the process, JumpBox delivers preconfigured Web apps that run as virtual appliances on any machine, across platforms, irrespective of operating system.
Use xfs_fsr to keep your XFS filesystem optimal
The XFS filesystem is known to give good performance when storing and accessing large files. The design of XFS is extent-based, meaning that the bytes that comprise a file's contents are stored in one or more contiguous regions called extents. Depending on your usage patterns, some of the files contained in an XFS filesystem can become fragmented. You can use the xfs_fsr utility to defragment these files, thus improving system performance when it accesses them.
Mail server benchmarking with Postal
The Postal project includes three programs aimed at benchmarking mail server performance. The main program, postal, sends email messages to a specified list of destination addresses at a specified rate. Postal can let you see how fast your system can process incoming email and thus can help you measure improvements to your mail server when you are making software and hardware changes. For example, you can use postal to tell you whether switching to a different IMAP server will allow you to deliver more messages per second on the same hardware.
Improve system performance by moving your log files to RAM
The Ramlog project lets you keep your system logs in RAM while your machine is running and copies them to disk when you shut down. If you are running a laptop or mobile device with syslog enabled, Ramlog might help you increase your battery life or the life of the flash drive on your mobile device. As a side effect of using Ramlog, you will be less likely to be caught out by a daemon that suddenly starts sending a message to syslog every 30 seconds and saps your battery keeping the hard disk spinning.
Monitoring network performance with GNetWatch
GNetWatch is a network monitoring and performance testing tool that lets you can see the status of hosts on your network, send ping requests of varying size and quality of service to hosts, and investigate SNMP information. GNetWatch includes support for using Wireshark and nmap to snoop packets and investigate hosts on the network.
IOzone for filesystem performance benchmarking
IOzone lets you benchmark your filesystem performance, seeing how well record IO occurs for files of various sizes. With IOzone you can see more detailed information than the read, write, and rewrite figures that Bonnie++ reports. IOzone is great at detecting areas where file IO might not be performing as well as expected.
A new utility for quickly interpreting multiple Bonnie++ benchmarks
Yesterday I discussed the Bonnie++ tool, which can be used to benchmark filesystem performance. When you are tweaking a RAID and filesystem combination, you generally want to see whether your changes work in a positive manner across the board, and by how much. I created a utility called bonnie-to-chart to show the results of multiple Bonnie++ runs in either absolute or relative performance terms. It's primarily a Perl script that can be used together with the Open Flash Chart component.
Using Bonnie++ for filesystem performance benchmarking
Bonnie++ allows you to benchmark how your filesystems perform various tasks, which makes it a valuable tool when you are making changes to how your RAID is set up, how your filesystems are created, or how your network filesystems perform.
Three reasons why GNU/Linux is better for Web servers than OS X
Apple's OS X, which has been an official certified Unix system for some time now, is often installed onto Internet-exposed or intranet-only Web servers for serving up dynamic content. I've worked with such configurations for a couple of years, and with GNU/Linux alternatives for even longer. There are at least three reasons why GNU/Linux systems do the job better.
Synchronize directories with Komparator and KDiff3
If you work some of the time on your laptop and some of the time on your desktop box, making sure that your work is updated on both machines is a must. Many tools can help you accomplish this, from command-line tools such as scp and rsync to generic graphical applications like Konqueror or Krusader, to more specific tools like Unison. Komparator and KDiff3, a couple of KDE applications with interesting features, may offer better ways of syncing your work.
How to save time and traffic upgrading with apt-proxy
June is Bandwidth Conservation Month (well, not officially, but let's say that it is), so if you have multiple machines running an APT-powered Linux distribution such as Debian or Ubuntu, you should take a look at apt-proxy, a utility that caches package downloads in a shared pool for all interested parties on your LAN. This saves you both the time and the bandwidth it costs to download the same updates for more than one computer.
PackageKit finds sweet spot in quest for universal package tools
Different GNU/Linux distributions provide incompatible systems for package management, and to date no one has quite figured out a foolproof way to get the best of them all. But where the alien utility tries to convert between major package formats, and Smart and Klik try to imagine new, universal forms of software installation, PackageKit has the more modest goal of supplying a universal front end that leaves the native package systems intact underneath. As Richard Hughes, the project lead for PackageKit, puts it, "PackageKit is a glue layer between the distro-specific parts, and some prettiness."
Build your own ultimate boot disc
You turn on your trusty old Linux box, and things are going well as you pass through the boot loader, until the disk check reveals that your hard drive partition table is corrupt, and you are unable to access your machine. You need a good rescue disk -- and the best way to get one is to create your own.
Monitoring network performance with speedometer
Speedometer shows a graph of your current and past network speed in your console, letting you see your network connection's up and downstream speed and history at a glance. You can also use speedometer directly on a file to monitor the download performance and history of a specific download instead of all network traffic. When displaying the total network traffic, speedometer is sort of like gkrellm, in that you can see the current and past network performance on a graph, but you can easily run it over an SSH connection without having to set up gkrellmd.
Benchmarking NFSv3 vs. NFSv4 file operation performance
NFS version 4, published in April 2003, introduced stateful client-server interaction and "file delegation," which allows a client to gain temporary exclusive access to a file on a server. NFSv4 brings security improvements such as RPCSEC_GSS, the ability to send multiple operations to the server at once, new file attributes, replication, client side caching, and improved file locking. Although there are a number of improvements in NFSv4 over previous versions, this article investigates just one of them -- performance.
Phoronix Test Suite brings Linux benchmarking to the desktop
Despite a variety of open source testing tools, until recently there wasn't an easy way to measure and compare the performance of two Linux-powered machines. Phoronix Test Suite (PTS), released this month, addresses this -- and how! Using the suite you can gauge and compare multiple Linux-powered machines to find out if a particular setup is better than another for a particular task, such as hosting a Web server or playing games.
Using ZFS though FUSE
ZFS is an advanced filesystem created by Sun Microsystems but not supported in the Linux kernel. The ZFS_on_FUSE project allows you to use ZFS through the Linux kernel as a FUSE filesystem. This means that a ZFS filesystem will be accessible just like any other filesystem the Linux kernel lets you use.
Smart ACL management with Eiciel
The traditional file permission model, where read, write, and execute permissions are set on each file for the user, group, and others (UGO) has one drawback: It can't be used to define per-user or per-group permissions. For that, you need to employ access control lists (ACL). Eiciel is a graphical tool that integrates with the Nautilus file manager and allows for easy ACL management.
eBox unites platform networking services
eBox is a server framework and platform that allows administrators to set up network services such as Lightweight Directory Access Protocol (LDAP) or a firewall from scratch relatively easily. eBox does not offer management of every option found in all service configuration files. Instead, it focuses on managing network-centric services and messaging applications easy by offering a single Web GUI portal. In addition, eBox can be extended by programmers who wish to add other services and management modules of their own.
Easy automated editing of /etc/files with Augeas
The days of parsing configuration files with awk and making quick changes to configuration files with ad-hoc scripts may finally be at an end. With Augeas you can forget about the parsing and focus completely on what settings must be changed. So if the configuration file moves a piece of data to the fourth column, you don't need to care; Augeas will still show it to you as it did before.
