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Building an LDAP Server on Linux, Part 1

Post date: April 15, 2005, 17:04 Category: Network Views: 3272 Comments
Tutorial quote: Your network is growing in size and complexity. It's taking on a life of its own, spreading and growing and absorbing everything in its path. You're tearing your hair out trying to keep track, and your users have somehow discovered your secret phone number and are pestering you with endless questions and demands--where do I find this; I don't want to keep track of a dozen different passwords; nothing works like it should.

Of several possible solutions, consider two: 1) find a new hiding place, or 2) implement an LDAP server. While finding a new hiding place might sound ideal, it's an option we're going to have to save for a future article. This series will instead explain what LDAP is good for, detail how to build an LDAP server, and cover what you can do with it.
Linux

The Serial Console

Post date: April 14, 2005, 13:04 Category: Hardware Views: 3970 Comments
Tutorial quote: In these modern times, a hardworking admin might be tempted to turn her back on the Old Ways, and indulge in increasingly exotic methods of interfacing with servers: SSH over ethernet, USB, Firewire, wireless, infrared, KVM switches, VNC, VPN... next stop: direct neural implants.

There's one old timer that still has useful place in the admin's tool kit: the serial console. Sure, it's slow and funky. But there are times it can be a real lifesaver. When nothing else works, it's a direct pipeline into your system. It's simple and cheap. You don't need to install drivers or expansion cards, it's just there.

Administration via serial console is common in data centers. Just imagine the nightmare of trying to connect all those rack units to keyboards and displays. The cabling can be extended to a nice comfortable ops center (well, an ops center, anyway). (This Lantronix Console Manager is an example of the type of device used to administer these.)

There are a number of ways to make the physical connection. You can connect an external modem--the kind us old timers fondly refer to as "real" modems--and do remote administration via dialup. It couldn't be any simpler, just dial direct. Or grab a null modem cable, connect to a laptop or a nearby workstation, and you have an instant terminal.
Linux

Tuneups and Tweaks for the Better Spam-Trap

Post date: April 14, 2005, 13:04 Category: Network Views: 3259 Comments
Tutorial quote: In parts 1 and 2 of our thrilling "Building an Anti-Virus/Anti-Spam Gateway" series, we covered the basic steps for setting up SpamAssassin and Clam Anti-virus with Postfix. This installment is devoted to testing and tweaking, and creating whitelists in Amavisd-new. Whitelists are essential when you set up any kind of spam filtering: It's the best way to make sure your wanted mail gets through.
Linux

Feed Your Virus Worries to a Clam

Post date: April 14, 2005, 13:04 Category: Network Views: 3438 Comments
Tutorial quote: Last week, we looked at how to set up SpamAssassin with Postfix, as part of a lean, mean, spam-killing gateway machine. This week we'll add an anti-virus scanner to our bubbling brew.
Linux

SpamAssassin and Amavisd

Post date: April 14, 2005, 13:04 Category: Network Views: 3365 Comments
Tutorial quote: The bad news is, it's SpamAssassin, not SpammerAssassin. The good news is it kills spam quite effectively, and fits nicely into an anti-spam, anti-virus gateway. This article, which shows how to use SpamAssassin with Postfix, is the first in a series on building an anti-spam and anti-virus gateway. This gateway works equally well for a single PC, or for a large network.
Linux

Sawing Linux Logs with Simple Tools

Post date: April 14, 2005, 12:04 Category: Security Views: 3444 Comments
Tutorial quote: So there you are with all of your Linux servers humming along happily. You have tested, tweaked, and configured until they are performing at their peak of perfection. Users are hardly whining at all. Life is good. You may relax and indulge in some nice, relaxing rounds of TuxKart. After all, you earned it.

Except for one little remaining chore: monitoring your log files. [insert horrible alarming music of your choice here.] You're conscientious, so you know you can't just ignore the logs until there's a problem, especially for public services like Web and mail. Somewhere up in the pointy-haired suites, they may even be plotting to require you to track and analyze all sorts of server statistics.

Not to worry, for there are many ways to implement data reduction, which is what log parsing is all about. You want to slice and dice your logs to present only the data you're interested in viewing. Unless you wish to devote your entire life to manually analyzing log files. Even if you only pay attention to logfiles when you're debugging a problem, having some tools to weed out the noise is helpful.
Linux

Prep for Tomorrow with an IPv6 Testbed

Post date: April 14, 2005, 12:04 Category: Network Views: 2976 Comments
Tutorial quote: Yes, friends, I am afraid you do have to start paying attention to IPv6 (Internet Protocol version 6). It's on its way, it's inevitable, and us ace network admins must learn to use it.
Linux

Upstream Provider Woes? Point the Ping of Blame

Post date: April 14, 2005, 12:04 Category: Network Views: 3084 Comments
Tutorial quote: Your users are complaining that "the Internet is, like, all slow." Users are always complaining, but you're seeing a lot of timeouts when you check mail, surf the Web, or try to log in for remote administration. Or even worse, latency is so bad that you keep getting killed all to heck in your favorite gory violent online multi-player game, so you know there is a problem. But there a lot of potential bottlenecks between your PC and the outside world, like your Internet gateway, proxy server, firewall, Internet service provider, and so forth, so where do you begin?

One of the best and most versatile network tools you can have is a notebook PC running Linux. This lets you plug in anywhere to run tests and find out what is going on. Make it a nothing-to-lose box--don't keep data on it so you can wipe and reinstall the operating system as necessary, because you want to be able to run tests outside of firewalls. Don't run any services. You can put a minimal iptables firewall on it, as there is no point in being totally exposed, but keep it simple. (Use MondoRescue to make a system snapshot for fast restores.)
Linux

How to set up mouse scroll wheel

Post date: April 14, 2005, 01:04 Category: Desktop Views: 3264 Comments
Tutorial quote: How can I set up my mouse scroll wheel in Xorg or XFree86? Here is quick solution :)
Linux

Mastering the Enterprise Volume Management System

Post date: April 13, 2005, 19:04 Category: System Views: 3384 Comments
Tutorial quote: The Enterprise Volume Management System, or EVMS, is a disk, partition, and file system manager for Linux that claims to be a comprehensive tool for all disk management tasks. I ran across EVMS and found the idea appealing, so I decided to try it out. I've been working with it for a couple of weeks now, and this article describes what I found.
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