Drew's Blog

For years now, I’ve had to run vpnc after connecting my school’s wireless. Truly, it never bothered me; however, at my new job, I need to run route after I connect to their wireless. For whatever reason, that got to me. I didn’t really want to run route when I wasn’t on their network (it likely wouldn’t have screwed anything up, but still…). So, I went about putting a quick bit in /etc/sysconfig/network-scripts/ifup-wireless, and it didn’t work… =\ So, after some digging, I’ve found another way using NetworkManager. Here’s what I did:

Because I hate hacking up scripts that services use, I wrote a quick script and put it in /usr/local/bin/wireless.sh:

Once that was done, I ran:

and added the line:

to the file /etc/NetworkManager/dispatcher.d/00-netreport right before the exit.

And that’s it! It would be neat if NetworkManager added in similar functionality through the GUI, but until that day, this should work fine. Also, to note, those scripts are run as root, so be careful!

Update!

Upon upgrading from Fedora 14 to 15, the file 00-netreport was overwritten. I’ve done updates to NetworkManager, so that had nothing to do with it. In any case, if you end up upgrading your distro, there’s a chance that’ll get overwritten. In the event it does, you’ll just have to paste the line to the script again. (Another good reason to use a script!)

There may be a better way than what I’m doing above, but it works for me, so I’m not going to bother looking for another way. Hope this helps!

Lately, I’ve been getting acquainted with Rails development at work. It’s been a pretty steep learning curve (for that matter, I guess it still is), but I’ve enjoyed it thus far. So, with my new found Ruby skills (or, I guess more-so my new found need to learn Ruby), I wrote a script that uses SSH to iteratively connect to every computer in a lab and update them. This could be used for just about anything, but for my instance it was updating a lab. There was a bit more to my script as I needed to recompile some device drivers when there was a new kernel, but for simplicities sake, I’ve ripped them out. Hope this helps someone else!

First, you’ll need to install the ruby-ssh library.

And, the script is:

And, that’s all there is to it! There’s a real lack of comments, but I feel it’s pretty self-explanatory. Enjoy!

I recently had the experience of setting up Postfix. It works really well, in my opinion; however, setting it up wasn’t the simplest for what I wanted. But, at least it was simpler than sendmail

Reading through several articles on the Internet, everyone was giving steps on how to setup postfix to handle e-mail for any FQDN (Fully-Qualified Domain Name). Well, we don’t want to be handling someone else’s e-mail, so we decided to set it up with authentication. All of the guides on setting up Postfix with SASL authentication are great and all; however, they don’t address the issue of, what if you want to receive mail as well. That’s a simple fix, but moreover, what if you have a service like mailman running? Mailman isn’t easily configured to authenticate against the SMTP server to send mail. So, the following are the configurations that I’ve come up with to solve all of these problems:

For the file /etc/postfix/main.cf

Now keep in mind, your values for some of the above WILL be different. This configuration is on a machine that’s running mailman as well (thus the /etc/mailman/aliases file).

And lastly, for SASL auth, edit the file: /usr/lib64/sasl2/smtpd.conf

Your lib64 directory may just be lib, depending on the architecture of your box. All of these edits were made a 64-bit Fedora 12 machine, but they should work for every machine.

And last note. After all of the edits have been made, make sure to restart postfix and restart saslauthd with the following:

/etc/init.d/postfix restart
/etc/init.d/saslauthd restart

For questions on what some of the postfix settings mean, you can check out one of the following:

postconf man-page by running “man postconf” or visit http://www.postfix.org/postconf.5.html

Postfix Documentation at: http://www.postfix.org/documentation.html

Postfix HowTo’s at: http://www.postfix.org/docs.html

Postfix is definition the easiest MTA I’ve ever had the pleasure of working with, as far as configuration goes. I hope this helps

I found this link on-line and found it to be quite useful.

http://www.beginlinux.com/server_training/web-server/976-apache-and-selinux

I refer to it often as I forget some of the commands once in a while when I add new files for Apache to serve.

I found this very useful article on running DBDesigner 4 on Fedora 8, here. I followed the directions and found it to work on Fedora 11 and Fedora 12. I’m sure it’ll work for just about any distro, so I’m just reposting the directions here as I find it to be a very useful program.

Do not use the original DBDesigner4 download available on the fabForce.net website. Instead download the dbdesigner-fork package from here:

http://sourceforge.net/projects/dbdesigner-fork/

Once you have unpacked it. Edit the bin/startdbd_using_kernel2.6 script and remove the assume kernel 2.4.1 text:

Original file contents: LD_ASSUME_KERNEL=2.4.1 LANG=en_US.ISO8859-1 LD_LIBRARY_PATH=./Linuxlib/ ./DBDesignerFork

Edited contents: LANG=en_US.ISO8859-1 LD_LIBRARY_PATH=./Linuxlib/ ./DBDesignerFork

Save it and run it. It should all work as expected on Linux Fedora 8 or indeed any other modern distribution like Ubuntu, etc.

For this, we’ll throw an .htaccess file into the directory you don’t want anyone to access that’s served via apache. For this, we’ll also have to have the following set for the directory in the httpd.conf file:

Here’s what the .htaccess file should look like (with a few modifications for location and network if you need):

And then in the same directory, create the .htpasswd file by:

Then when promptd, enter the password for that username. Make sure both files are owned by apache (or www-data if your webserver runs as such). Viola! It works.

(Note: To add more users that the htpasswd file, do the same command as above, without the -c)

If you get a message similar to this:

Error: rpmdb open failed

You can fix it by running the following 3 commands:

Okay, this will be short and sweet. Here’s how you clone a VirtualBox HDD in Windows:

“C:\Program Files\Sun\VirtualBox\VBoxManage.exe” clonevdi “C:\Users\Andrew\.VirtualBox\HardDisks\Windows XP.vdi” “C:\Users\Andrew\.VirtualBox\HardDisks\Windows XP Clone.vdi”

and in Linux:

VBoxManage clonevdi /home/andrew/.VirtualBox/HardDisks/WindowsXP.vdi /home/andrew/.VirtualBox/HardDisks/WindowsXPClone.vdi

The basic form is “VBoxManage clonevdi sourcevdi destinationvdi”. Now you may ask, why clone a virtual machine’s hard drive? Well, if you want to back them up, this works for that. Or, if you want to duplicate that same virtual machine without having to do a second installation/activation.

Also to note, doing it this way will change the HDD’s UID, so you don’t get the error: “A hard disk with UUID {92c7da90-00f3-4bda-b338-57d24dad7f4b} or with the same properties (’/home/andrew/.VirtualBox/HardDisks/WindowsXP.vdi’) is already registered.”

Also, last thing to note… Instead of the directory “HardDrives”, yours may be “VDI”. I believe in older versions of VirtualBox it was VDI; however, these days it’s HardDrives.