Linux self-education links.

How to Install Postfix on Ubuntu

(argh, forgot to back up my postfix work. i have to start fresh, so this is an opportunity to document work.)

# first get a superuser shell with sudo
sudo -s

apt-get install mailutils
apt-get install postfix
apt-get install mailman
apt-get install spamassassin
apt-get install courier-imap
apt-get install courier-imap-ssl
apt-get install courier-pop
apt-get install courier-pop-ssl

# unfortunately, we need to install apache2 because we're going to install
# the roundcube mail client

apt-get install apache2
apt-get install roundcube

One-Liner to Install Java JDK into /usr/local/bin

There's a zillion ways to do it, and editing $PATH is probably the best, but I didn't want to do that, so I did this:

for i in ` ls /usr/local/java/jdk1.7.0_21/bin/ ` ; do echo $i ; ln -sf /usr/local/java/jdk1.7.0_21/bin/$i $i ; done

That symlinks all the stuff in bin into /usr/local/bin, which is already in the $PATH.

Adding a Disk to a Linux System using Command Line Tools

I was faced with installing a new disk on a home server, and while I've done this a hundred times, it seemed to be difficult enough to deserve yet another tutorial, if only for my own reference. It's not hard, but until the new GNOME GUI tools were developed, it was a kind of complex process. (It's complex on all Unixes, for some reason. BSD is even more difficult than Linux.)

Debian and Ubuntu Networking Configuration /etc/network/interfaces with a Static IP Address

This is easy to find anywhere, and it's here too. This one includes the dns-* lines that will be read by resolvconf(8).

root@server:/etc/network# cat interfaces
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
auto eth0
iface eth0 inet static

Migrate to a New Server for Exim4 + Spamassassin + ClamAV

I've done this three times now, and it's pretty simple. If you're using a VM environment, 1GB RAM and 5GB of disk are enough.

EasyCZ Button Switchboard

This is a simple (or simplistic) Linux GTK+ application that shows a button panel or "switchboard". Each button executes a script.

Headaches from Configuring Authentication and Encryption for Unix MTAs

Though I'm now officially an Exchange hater, there's still one thing that really sucks about running a Unixy email server: authentication and encryption.

It's been hard to configure for years - Sendmail, qmail, and now exim4, have put me through the grinder when it comes to setting up authentication, particularly authentication for SMTP relaying.

Out of box, the mail servers in the Debian and Ubuntu distros seem to be configured to relay email for your localhost, and that's all.

ZyXEL - ZyWALL USG 50 First Impressions

We just got one of these. It's a low-cost firewall. Some folks on forums have said that ZyXEL uses a proprietary OS, ZyNOS, and perhaps they do, but not on this device. The latest firmware download includes a spreadsheet with FOSS software listed, and it includes the Linux kernel and a bunch of popular networking software.

I haven't built Linux firewalls in a few years, so I'm out of touch. The firewall feels a little Linuxy, but there's a layer of configuration objects that helps to glue all the different services together.

USB Booting System for Clonezilla SE, Diskless PC

(This article is good, but somewhat obsolete. I'm now doing something slightly different.)

This mini project took a USB hard drive, made it bootable, and then used it as a disk cloning network. It's worked very well.

Hauppage WinTV-1600 on Linux

I bought this several months back, and finally installed it on the Linux box. It works, sort of. ATSC (HDTV terrestrial broadcast) works fine. FM Radio does not. More info:

Sysadmin Notebook

This is a collection of articles about system administration of Windows, Unix/Linux/BSD, and Macintosh computers and networks.

PHP Runs an Old Version of PCRE Causing Problems with Drupal and MediaWiki

This seems to happen a lot - and it took several searches and many pages of reading to find the solution. This page will try to even the odds a little more.

The solution was found here: PCRE Problem Appearing in PHP Related to Apache Webserver

After building a new Apache, then a new PHP, and configuring both, Drupal started throwing error messages "Compilation failed: this version of PCRE is not compiled with PCRE_UTF8 support".

Payment Card Industry Data Security Standard (PCI DSS), getting with the program.

These are notes for achieving conformance with PCI DSS.

Automatically Restart Apache when it Freezes

This is a rough watchdog script to restart apache on the local machine when the website gets slow. If a GET to the url fails, or takes longer than 60 seconds, the local web server is restarted.

I started to use this after installing a new version of Apache. The system hadn't been properly tuned, and the side effect was that Apache would be nearly wedged, but the rest of the system was merely slow. This happens when Apache or MySQL are getting wedged, but it's not due to the system overloading with too much traffic. Why does it happen?

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