Monitoring Filesystem Events with incron on RHEL 6

Have you ever wanted to know when a file is changed or accessed by the system or user? There is a program that does just that task called Inotify cron (incron). Incron is for monitoring filesystem activity. It consists of a daemon and a table manipulator. You can use it a similar way as the regular cron. The difference is that the inotify cron handles filesystem events rather than time periods incron... read more

Install Tomcat 7 and Java 1.7 on CentOS 6 RHEL 6

In this post we will cover how to install the Apache Tomcat 7 and jre 1.7 on CentOS 6 and RHEL 6. This process doesn’t use the rpm’s from the Redhat repositories, but uses the latest tar balls from Apache and Oracle. We will also be using service accounts to control Tomcat and its processes. Download latest Tomcat from Version 7.0.40 is the curent... read more

How To Fix RHEL / CentOS 6.4 LDAP MD5 Cert Error

Recently we updated to the latest RHEL 6.4 which caused LDAP to stop using our MD5 signed  certificate. This was due to the nss-3.14.0 update that now deems MD5 as unsecure. This change caused authentication of users using LDAP to fail. If the account had a local password (such as root), they were able to login. Since creating / updating the MD5 certificate was not an immediate solution for us we had to... read more

How to set a Directory Sticky Bit in Linux

There are times on Linux / Unix that you need to set the permissions on a directory so that only the owner and root can delete / rename files or sub-directories in the directory. This is true by default with the /tmp directory. This is commonly referred to as the sticky bit. If you want to keep the permissions the same on the directory and just add the sticky bit you can do this by using the chmod command... read more

How to lock down files in Linux using chattr

As system admins there is always a few trouble users that keep changing files we don’t want them to, such as /etc/resolv.conf. We can do that using the chattr command. Here is the file with no flags using the lsattr command. lsattr – list file attributes on a Linux second extended file system $ lsattr resolv.conf ————-e- resolv.conf So lets lock down the file using -i... read more

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