Script to clear memory during long running jobs on a centos cluster.

Another interest that has turned into real work is my tinkering with HPC Linux clusters and Linux in general, in this area I will blog and post particular commands that have helped me solve problems, I’m not saying these are the best ways but have worked in my environment, and yes Google, Yahoo and Bing have assisted.

I created my favorite directory to hold the script
# mkdir /filemisc

In my favorite directory I create the script file to clear the memory
# cd /filemisc
# vi

I add the following line to the file
sync ; echo 3 > /proc/sys/vm/drop_caches

Now we need to change the file mode so cron can run the file
# chmod 775 /filemisc/
Now add the /filemisc/ to cron with your execution time and date, in this example the script runs every 120 minutes.

# crontab –e
Now add the following to the cron file and execute the vi write and quit command.
*/120 * * * * /filemisc/

Posted in HPC Linux Clusters | Leave a comment

Verizon Business Customer Information Is Hacked – Fortune

Hackers supposedly stole customer contact information.

Verizon’s division that helps Fortune 500 companies respond to data breaches, has suffered a data breach of its own.Customer contact information supposedly stolen from Verizon’s enterprise unit appeared online earlier this week, reports Brian Krebs, an independent cybersecurity journalist. He happened upon the cache while trawling the web.During his search, Krebs noticed that “a prominent member of a closely guarded underground cybercrime forum posted a new thread advertising the sale of a database containing the contact information on some 1.5 million customers of Verizon Enterprise,” as he writes on his site, KrebsOnSecurity. Whoever posted the notice set the total price at $100,000 or alternatively at $10,000 per batch of 100,000 records, Krebs reports. The seller also offered up information about vulnerabilities affecting the company’s website for money.Verizon VZ -0.48% confirmed the incident to Fortune, but not say whether the numbers reported by Krebs are accurate.Read more: “The hotly disputed black magic of data breach cost estimates”“Verizon Enterprise Solutions recently discovered and fixed a security vulnerability on our enterprise client portal,” a spokesperson told Fortune in an email. “Our investigation to date found an attacker obtained basic contact information on a number of our enterprise customers.”

Source: Verizon Business Customer Information Is Hacked – Fortune

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Best Practices for Home Network Security – Limit Privileged User Accounts


In your computer operating system, the privileged administrator (or root) account has the ability to access any information and change any configuration on your system. Therefore, web or email delivered malware or viruses can more easily compromise your system if executed while you are logged on as an administrator. Create a non-privileged “user” account for the bulk of your activities including web browsing, e-mail access, and document creation/editing. Only use the privileged account for reconfigurations or software installations/updates.

Posted in Home Network Security, Uncategorized | Leave a comment

Best Practices for Home Network Security – Install Security Software

Install a security collection that provides defense for anti-virus, anti-phishing, safe browsing and firewall capabilities. In addition, some security suites provide access to a cloud-based reputation service for leveraging corporate strength malware services. Be sure to enable the software’s automatic update service to keep signatures up to date.

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Best Practices for Home Network Security – Use Updated Software

Migrate to a Modern Operating System and Hardware Platform. The latest version of any operating system (OS)inevitably contains security features not found in previous versions. Many of these security features are enabled by default and help prevent common attacks. In addition, using a 64-bit OS on a 64-bit hardware platform substantially increases the effort for an attacker to obtain privileged access on your computer.

Posted in Home Network Security | Leave a comment

Lockdown: How to secure your PC without going crazy | PCWorld

A strong password is the first, best line of defenseGood computer security and privacy begins with strong passwords. Sure, there are serious criticisms about how online services use passwords, and Apple may be trying to take biometrics mainstream with TouchID on the iPhone 5s, but for now passwords are still the best solution we have for keeping third parties away from our data.

Source: Lockdown: How to secure your PC without going crazy | PCWorld

Posted in Security Technology | Leave a comment

Reasons For PC Security

A few reasons to secure your PC just as corporations secure their networks. Most people have some financial and identity information on their home PC such as tax, banking or credit card information. Many PCs contain personal family information such as pictures they do not want stolen and posted on the internet. Today’s threats include malware such as crypto locker that will completely encrypt your hard drive until you pay a ransom.

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Loading OMD Centos 5.8 (article copied from Maxwhale better way to install nagios)

I experienced the following error using Cento 5.8 and omd-0.56-rh60-29.x86_64.rpm so this article had the solution that worked for me!

Missing Dependency: boost-program-options is needed by package

install epel repository on CentOS 6

rpm -Uvh

Install epel repository on CentOS 5

rpm -Uvh

This is URL for latest file, better check before running following command.

For 64bit CentOS 6 or CentOS 5


For 32bit CentOS 6 or CentOS 5


Run below command if 64bit OS installed

yum install –nogpgcheck omd-0.54-rh60-28.x86_64.rpm

Run below command if 32bit OS installed

yum install –nogpgcheck omd-0.54-rh60-28.i386.rpm

omd create prod

su – prod

omd start

If you experienced those error during installation:

–> Missing Dependency: boost-program-options is needed by package

Download For 64bit OS:


Download for 32bit OS:


Install the rpm file

rpm -Uvh boost-program-options-1.39.0-9.el5.x86_64.rpm


rpm -Uvh boost-program-options-1.39.0-9.el5.i386.rpm

based on your 32bit/64bit OS.

and then rerun

yum install –nogpgcheck omd-0.54-rh60-28.x86_64.rpm


yum install –nogpgcheck omd-0.54-rh60-28.i386.rpm

Start up messages from my actual startup[root@localhost ~]# omd create prod
Adding /omd/sites/prod/tmp to /etc/fstab.
Creating temporary filesystem /omd/sites/prod/tmp…OK
Created new site prod with version 0.56.

The site can be started with omd start prod.
The default web UI is available at http://localhost.localdomain/prod/
The admin user for the web applications is omdadmin with password omd.
Please do a su – prod for administration of this site.

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How to Reset a Cisco ASA 5505 Back to Factory Default

A power issue at a site (or someone at the site trying to help) fried the running config of an ASA 5505, so I used the steps found below to return the unit back to factory defaults and then restored a previous configuration into the unit.

type ‘enable’ to go to enable mode. Enter the password, or simply press enter if there is no password.

type ‘config t’

type ‘config factory-default’

type ‘reload save-config noconfirm’

The Cisco ASA has been reset to factory settings. DHCP is enabled on the cisco device, and it’s internal IP address is now!

If you had an enable password, you may need to enter that in the password box when you connect using  ASDM, otherwise the default username and password are both blank.

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Used Knoppix 6.2.1 ADRIANE to recover data from a failed Windows installation

I walked into my work area a few days ago to find a Dell XPS 400 that had been left for repair. I checked the system out and determined the hard drive was fine, but that the windows installation was corrupt (what a surprise right).

I downloaded Knoppix 6.2.1 ADRIANE and copied the image to a USB drive in order to boot the PC into Linux.

Next, I mounted the windows drive using the ADRIANE interface and copied the data the user requested with midnight commander to a USB Drive. Midnight Commander is included in the Knoppix distribution.

I am reloading Windows on the PC which is another set of issues; I will fill in the gaps as I have time. Suffice to say using Knoppix I recovered the data that the user needed and feel pretty good as they were told it could not be done!

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