I’ve seen this happen a few times, and it’s incredibly simple as to why: Somebody screwed up.

No. Really.

What’s happening about 90% of the time, is that there is a colission between installations. PHP usually uses a dynamic mysql library. Apache auth modules such as 2.2’s internal auth_dbd, and mod_auth_mysql also usually link against a dynamic mysql library.

If you happen to change your development mid-stream and don’t recompile everything, here’s where problems can occur.

To put it as non-geeky as possible: If the MySQL client is v5, and PHP uses this v5, but mod_auth_mysql is using v4, they both are asked to load, end up with with the same functions, and BAM.

It’s kind of like shouting “Hey, Steve!”, and having two guys answer “Yes?” The only difference is, UNIX doesn’t know how to act embarrassed and politely wave over the one that was intended.

Although, this analogy isn’t entirely true. It just makes it easier to understand. PHP wanted Steve v5, and mod_auth_mysql wanted Steve v4. So, when they both tried to call for Steve, both of them ended up in the same place.. which made bad things happen.

You can use ‘ldd’ to see which dynamic libraries are used by which programs, and other libraries.

# ldd /usr/lib/php4/20050606+lfs/mysql.so | grep mysql
        libmysqlclient.so.15 => /usr/lib/libmysqlclient.so.15 (0xb7d6e000)
# ldd /usr/lib/libaprutil-1.so | grep mysql
        libmysqlclient.so.15 => /usr/lib/libmysqlclient.so.15 (0xb7c56000)

Building limitipconn is fairly straight forward. It utilizes a simple Makefile build for the DSO object (which just uses apxs).

First, make sure you have all of the required libraries:

# apt-get install apache2-prefork-dev libapr1-dev

Here’s the simple diff from the default Makefile, to my modified one to ensure building. You can cut and paste this into vi, nano, or your favorite text editor, then apply to the Makefile included within the limitipconn package using patch:

—- Makefile.old        2007-04-27 17:50:57.000000000 +0200

+++ Makefile    2007-04-27 17:53:24.000000000 +0200

 -4,12 +4,12 
 ##


 #   the used tools
-APXS=apxs
-APACHECTL=apachectl
+APXS=/usr/bin/apxs2
+APACHECTL=/usr/bin/apache2ctl

 #   additional user defines, includes and libraries
 #DEF=-Dmy_define=my_value
-#INC=-Imy/include/dir
+INC=-I/usr/include/apache2 -I/usr/include/apr-1.0
 #LIB=-Lmy/lib/dir -lmylib

 #   the default target

All I did was update the Makefile to work with Debian’s installation for the utilities (differently ordered by the Apache major revision), and added the include directories, because the module’s author used indirect paths.

# cd /where/i/unpacked/limitipconn
# vi Makefile.patch (paste in my above patch, save and quit.)
# patch -p0 < Makefile.patch

Now, just make the module (This is almost cheating, but easier for folks not entirely familiar with the libtool build process):

#make install

Technically, it’s now installed. You can restart Apache and it will load. This isn’t 100% Debian friendly, as it uses /etc/apache2/httpd.conf, rather than the /etc/apache2/mods-*/*.{load|conf }heirarchy, but making it so is beyond the scope of this simple article.

I can, however, be coerced into doing so for money. ;)

If you haven’t noticed, yet, many of my recent developments have been for, and regarding Debian.

A current client is a RedHat Enterprise 4, CentOS, FreeBSD, and Debian shop, with Debian being on the front end. As the key systems are integrated to a unified OS approach, one of the most important aspects is to keep your front end systems up to date with security, first and foremost, then consistant features (with the legacy, where appropriate), and finally, new bells and whistles.

This ensures your deliverability; I can’t understand how large companies like YouTube manage to redirect people to a page saying ‘Sorry, guys, it’s that time of the week again. Everything’s down for a few hours.’

That’s awful design, and incredibly useless if your whole product is reliant on actually being available to make money.

Yet, I digress. This is now “Web 2.0” where the game seems to be “content over form.” All hail the new Emperor.. just as soon as he finishes touching up his body paint.

I’m all for commerce, and advertising is just a side effect of consumerism. However, I don’t want to see ads when I’m checking my bank account online. I consider this pretty crass, and sad that my bank would opt to allow such things.

Below is the information I’ve discovered to make it go away:

^{If you do not want to receive prescreened offers of credit from this or other companies, call the consumer reporting agencies toll free, 888-567-8688; or write: TransUnion Name Removal Option, P.O. Box 505, Woodlyn, PA 19094; Equifax Information Service Center, P.O. Box 740123, Atlanta, GA 30374-0123; or Experian Direct Marketing, P.O. Box 919, Allen, TX 75013.}

Thankfully, BofA made this fairly easy to find today (after three years of no opt out information). Perhaps they were sued.

This is incredibly simple, but it’s amazing how many people (ab)use Perl to do something that awk was designed for.

Here’s how to find your existing Linux styled ethernet interfaces:

%ifconfig -a | awk '(/inet\ addr/||/^eth/||/^lo/)&&!/127/ \
gsub(/inet\ addr:/, "") { print $1}'
eth0
10.10.0.212
eth1
85.92.154.212
eth1:1
192.168.30.1
lo
127.0.0.1

Those of you who might be able to read that will ask: Why not /127/? It’s a dummy test. :)