Tech.It.2.Me->{By.Anton.Perez}

First off, apologies for not have posting anything in the last few weeks.  I just got back from Manila, Philippines to visit my ill grandfather (read: father).  He made it, but is still weak.  I love you lolo!

Anyway, I personally run Red Hat Enterprise Linux 4 at work for any *nix tasks, and in this post I’ll show you how to install Yum for easier management.

According to Linux@DUKE: Yum is an automatic updater and package installer/remover for rpm systems. It automatically computes dependencies and figures out what things should occur to install packages. It makes it easier to maintain groups of machines without having to manually update each one using rpm.

So, without further adieu:

1.  Download yum-2.0.8-1.noarch.rpm from:

http://linux.duke.edu/projects/yum/download/2.0/yum-2.0.8-1.noarch.rpm

2. Install it with the following command:

rpm –i yum-2.0.8-1.noarch.rpm

3.  Configure your yum.conf [in /etc/yum.conf] like so:

[main]
cachedir=/var/cache/yum
debuglevel=2
logfile=/var/log/yum.log
pkgpolicy=newest
distroverpkg=redhat-release
tolerant=1
exactarch=1

#base]
#ame=Red Hat Linux $releasever – $basearch – Base
#aseurl=http://mirror.dulug.duke.edu/pub/yum-repository/redhat

/$releasever/$basearch/
[base]
name=CentOS-$releasever – Base
baseurl=http://mirror.centos.org/centos/4.4/os/i386/
gpgcheck=1

[updates]
name=Red Hat Linux $releasever – Updates
baseurl=http://mirror.centos.org/centos/4.4/os/i386/
gpgcheck=1

4.  Download the GPG key for CentOS RPM packages with:

wget http://mirror.centos.org/centos/RPM-GPG-KEY-CentOS-4

5.  Import the key like:

rpm –import RPM-GPG-KEY-CentOS-4

6.  Run yum -y update, sit back, relax, and enjoy watching your system being updated.

That’s it!  Now you can use yum to install anything you wish.  Ciao!

I use MySQL as my database server, and thankfully, it’s been reliable and easy to use.  A qualm I have, however, is that it doesn’t include a daily backup feature, unlike Microsoft SQL Server.

The good thing is that the open source community has seen this problem and created a solution for it: AutoMySQLBackup.  (You can download it from here.)

According to the website on SourceForge.net:

A script to take daily, weekly and monthly backups of your MySQL databases using mysqldump. Features – Backup mutiple databases – Single backup file or to a seperate file for each DB – Compress backup files – Backup remote servers – E-mail logs – More..

Here are the quick-and-dirty set up steps (courtesy of debianhelp.co.uk):

1.  Download automysqlbackup.sh and place it into your /etc/cron.daily directory like so: cp /path-to-automysqlbackup/automysqlbackup.sh /etc/cron.daily/.

2.  Edit (at least) the following lines via vim automysqlbackup.sh:
USERNAME=dbuser
PASSWORD=password
DBNAMES=”DB1 DB2 DB3″

3.  Make the file executable by typing: chmod u+rwx automysqlbackup.sh.

4.  Create the following directory by typing: mkdir ./backups.

5.  That’s it!  You can either run the script via the command line: ./automysqlbackup.sh, or let it run its course since we’ve now put it in /etc/cron.daily; make sure the cron service is running, though.  ;0)

Peace. \m/

I run my own mail server and use Squirrelmail to facilitate webmail access using HTTPS.  I encountered problems trying to delete a folder that I created as part of a test to find out if things were working correctly:

ERROR : Could not delete “Archive” 
Given: Invalid mailbox name

SquirrelMail is a Webmail application started by Nathan and Luke Ehresman and written in the PHP scripting language. It can be installed on almost all web servers so long as PHP is present and the web server has access to an IMAP and SMTP server

After some digging around, I found that after modifying a setting via ./conf.pl I was able to delete the folder.  If you’re experiencing the same thing, do the following:

1.   Open a terminal window.

2.   Navigate to Squirrelmail’s root dir, which in my case is /usr/share/squirrelmail.

3.   Navigate to the config/ folder then type: ./conf.pl.

4.   Select option 3 then 1 and enter none.

5.   Save your changes and exit.

It may not work on all situations, and some have said that in version 1.4.0, you may need to set/pick your IMAP server (I use Dovecot), like so:

1.   Open terminal window (again).

2.   Navigate to the config/ folder then type: ./conf.pl.

3.  From the menu options, select D, then save and exit.

If you still have problems after performing these steps, modify your php.ini config file to report more verbosely by changing the following lines:

display_errors = on
error_reporting = E_ALL

After saving the modifications you just made, restart your web server via (I run FC6 so) service httpd restart, then watch your Apache error_log for more info. 

That’s it.  Hopefully, this helps you from having to do the legwork.  Take care.  =0)

If you use MediaWiki to power your wiki, you’ve probably heard of the Bad-Behavior plugin to help fight spam.

Bad Behavior is a set of PHP scripts which prevents spambots from accessing your site by analyzing their actual HTTP requests and comparing them to profiles from known spambots. It goes far beyond User-Agent and Referer, however. Bad Behavior is available for several PHP-based software packages, and also can be integrated in seconds into any PHP script.

I was all for it after I read the description as well as the functions it adds to one’s wiki.  So, I did the following:

1.   Downloaded it like so:

wget http://www.bad-behavior.ioerror.us/download/bad-be…

2.   Unzipped it with the -a option (for ASCII mode):

unzip -a bad-behavior-2.0.10.zip

3.   Copied the whole folder to /path-to-wiki/extensions

cp -R /path-to-wiki/extensions

4.   Edited LocalSettings.php an added the following line at the end of the file:

include( ‘./extensions/Bad-Behavior/bad-behavior-mediawiki.php’ );

The include statement above should’ve worked where a new table would’ve been added in my MediaWiki DB, but this did not happen, and when clicking on any link, I would just get a blank page.

My HTTPD logs also showed “undefined variable” errors, so after searching for fixes, I found that the following line had to be added just below the require_once(“includes/DefaultSettings.php”) line to resolve the issues. 

Apparently, you’ll need this if you’re using a certain combination of Apache-PHP-MediaWiki versions:

require_once( “includes/DatabaseFunctions.php” );

I restarted Apache and all worked fine.  You can also add the Bad-Behavior 2 Extended extension if you’d like, which I did.

Over the weekend, I finally installed and configured my own e-mail server. What a challenge that was!

I’m successfully running Postfix, Dovecot, Spamassassin, Amavisd-new, ClamAV, SQLgrey, and Squirrelmail. I, however, encountered problems sending to Gmail.

It returned with the following message:

host gmail-smtp-in.l.google.com[64.233.163.27] said:
550-5.7.1 [76.170.212.236] Our system has detected an unusual amount of unsolicited 550-5.7.1 mail originating from your IP address. To protect our
550-5.7.1 users from spam, mail sent from your IP address has been 550-5.7.1 rejected. Please visit 550-5.7.1 http://www.google.com/mail/help/bulk_mail.html to review 550 5.7.1 our Bulk Email Senders Guidelines. 39si20019987nzk (in reply to end of DATA command)

Rejected? Huh? Apparently, my IP address has been blacklisted because Google couldn’t identify my server; also because I don’t have a static IP.

They said:

To ensure that Gmail can identify you:

• Use a consistent IP address to send bulk mail.
• Keep valid reverse DNS records for the IP address(es) from which you send mail, pointing to your domain.
• Use the same address in the ‘From:’ header on every bulk mail you send.

We also recommend publishing an SPF record, and signing with DomainKeys.

At this point, I don’t really want to run and maintain my own DNS server nor obtain a static IP (everything works fine and it’s cheaper!), so I found a way around it: Set Postfix to use another SMTP server.

Here’s how:

1. Edit /etc/postfix/main.cf, and add or edit this line:

relayhost = smtp.servertouse.com

2. Restart the Postfix service (I run FC6), so:

sudo service postfix restart

That’s it! Your server will now send to the SMTP server specified above rather than sending directly to the destination, which as a result, will not be “rejected” by Gmail or the like. ;0)