Technology Insights

Ubuntu apt-get upgrade – The following packages have been kept back

When upgrading packages on Ubuntu using the apt-get upgrade command you may notice that some packages are not upgraded. Ubuntu will not upgrade packages that could have a major impact to service on the server such as the kernel, kernel headers, MySQL packages, and various others. The packages are held back by aptitude as a safeguard to keep people from upgrading packages that might keep the server from rebooting or that might corrupt something like a database. Below we show the error in more detail and explain the command that can be run to upgrade the packages that are being held back.

Technology Insights

JTR – John The Ripper Compile Error – common-opencl.h:8:19: fatal error: CL/cl.h: No such file or directory

Recently while attempting to get John The Ripper 1.7.9 jumbo-7 working on a Ubuntu 12.04 LTS Linux server with multiple AMD GPU cards in it I ran across an error during the compile process. The error complained about the VL/cl.h file not being installed and thus could not finishing compiling. Below I describe the compile error, how to locate the Ubuntu package that installs the necessary file to move past the previously mentioned compile error, and then how to install the correct package.

Technology Insights

JTR – John The Ripper Compile Error – sha.h:4:25: fatal error: openssl/sha.h: No such file or directory

Earlier while compiling JTR or John The Ripper password cracker on a new Ubuntu 12.04 LTS server I received a compile error. The error compiling JTR, which is noted in more detail below, pointed to the sha.h file not being found which likely means there is a missing package though I have seen other causes for file versions being incorrect. Below I explain the initial compile error in more detail, how to track down the package that provides the necessary file or files, and how to install the necessary package on Ubuntu.

Technology Insights

Ubuntu 12.04 View Package Version

While working to verify some packages in Ubuntu 12.04 had backport patches installed properly I needed to list installed package versions. To do this you can install a package called apt-show-versions which will allow you to list all installed packages and their versions with ease. This likely works on most Ubuntu versions but was tested on Ubuntu 12.04 also know as Precise PangolinĀ and Ubuntu 12.10 also known as Quantal Quetzal. Follow the instructions below to install apt-show-versions and then list all installed packages and their versions.

Technology Insights

Authenticate Linux To Active Directory On Windows – Centrify Express

I was working with a coworker today to setup a new Redmine server running on top of Ubunut 12.04 and one of the steps we completed in the process was setting up LDAP authentication in Redmine. Setting up LDAP authentication in Redmine requires the server running Redmine to be joined to the Windows Active Directory domain so I needed a quick way to auth Linux on Active Directory. I have used Centrify in the past and remember it being really easy to setup authentication from any form of Linux to a Windows domain and again it did not disappoint. Follow the directions below to join a Linux server to Active Directory using Centrify.