Category Archives: Ubuntu

Fix: No Sound / On-Board Sound disabled after installing new Video Card with HDMI

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This was a frustrating error that I found numerous possible fixes to on-line on various forums which involved installing the latest nightly builds and completely flushing out my drivers and rebuilding them. None of this worked, which led to hours of frustration. Finally, I tried a very old fix that I used to use for Sound Blaster (dating myself here…) back in the 90’s to get the games Doom or DukeNukem to load properly.


This fix will require you to know a little bit about CMOS and BIOS and is designed to fix the HDMI on the video card from over-riding the onboard sound.

1. Boot up into your BIOS – This is usually the F1 / DEL / F2 Key on first starting the computer.

2. Locate the Advanced tab for your PCI card settings, you are looking for the Interrupt settings which will be a list of features with assigned “IRQ”‘s next to them. Every system has these.

3. Locate the HDMI Sound Interrupt – Regardless of the value for the IRQ, set it to disabled.

4. Once its disabled, Save the changes to BIOS and reboot. Once the system starts you should have your On-Board sound again.

The issue is occurring because it appears that the HDMI on the video card is grabbing the interrupt for the on-board sound system and overriding it on every start up. I have tested this on Windows 10 and Ubuntu 14.04, 16.04 and 18.04 for Nvidia brand cards. Once the above change was made everything works well.

SpamAssassin not Filtering certain domains

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Problem: Spamassassin is not properly filtering domains such as link, click, xyz, science, and similar.

Solution: Your Registrar Boundaries file is out of date.

In Ubuntu, go to /usr/share/perl5/Mail/SpamAssassin/Util/

Use: wget svn.apache.org/repos/asf/spamassassin/trunk/lib/Mail/SpamAssassin/Util/RegistrarBoundaries.pm  (It will probably download as RegistrarBoundaries.pm.1)

cp RegistrarBoundaries.pm to RegistrarBoundaries.pm.old

cp RegistrarBoundaries.pm.1 to RegistrarBoundaries.pm

sudo service spamassassin restart

Enjoy!

 

SSH, SASL, Hackers, and more…

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SSH (Port 22 if you haven’t moved it) and the SASL mail authentication will get hammered with Brute force attacks on a regular basis if a system is available on the Internet.  However, there are ways to mitigate these attacks…

Fail2Ban for Linux bases systems does an excellent job of stopping these kinds of attacks.  These instructions are for installing fail2ban on a Ubuntu Server 14.04.

From the Command-Line and a sudo authorized account:

Sudo apt-get update

sudo apt-get install fail2ban

Copy the Config file: sudo cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local

Edit the Config: vi or nano /etc/fail2ban/jail.local

Bantime is defaulted to 600 seconds (10 Minutes), I prefer 1200 (20 minutes) or 1800 (30 Minutes) since most clients that trigger the ban are well deserving.

Maxretry defines how many attempts in Findtime (600 Seconds or 10 Minutes) a user can try to login before triggering the ban.  3 attempts in 10 minutes is a great qualifier for a web server, if its a server in a production environment that has multiple users leveraging ssh, you may want to raise the attempts.

You can then turn fail2ban on for other web services towards the bottom of the configuration file.

 

Shellshock Patch

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Symptoms: Your system is susceptible to the Shellshock Patch, unless you have updated in the last two weeks, this is probably the case.  This article applies to Linux based systems.

Solution:  In Ubuntu, run sudo apt-get update, then run sudo apt-get install bash.  This will update your system against the latest vulnerability.

If you are using centos, use yum.