RHEL6 features

1. It uses UUID instead of labels for the disks

which means in /etc/fstab you will mention UUID=”xsdfdfs123sdf” /mnt ext4 defaults 1 2

you do not need e2label command any more, but you need blkid command, using command you will find uuid of a partition.

2. After creating new partition you have to reboot the system to updated kernel partition table or use commands “partprobe or kpartx” to update kernel partition table.

3. RHEL6 uses two new strong password hasingh i.e. SHA-256 (algorithm 5) and SA-512 (algorithm 6)

4. Default Mail Transfer Agent (SMTP server) is PostFix not Sendmail

5. System Security Services Daemon (SSSD) implements a set of services for central management of identity and authentication.

–Note these are few features I noticed

puppet – configuration management tool

Puppet is a tool designed to manage the configuration of Unix-like and Microsoft Windows systems declaratively. The user describes system resources and their state, either using Puppet’s declarative language or a Ruby DSL (domain-specific language). This information is stored in files called “Puppet manifests”. Puppet discovers the system information via a utility called Facter, and compiles the Puppet manifests into a system-specific catalog containing resources and resource dependency, which are applied against the target systems. Any actions taken by Puppet are then reported. more

Video which gives demo on puppet

excellent tcpdump command to find network details for interface and their VLAN details

tcpdump -nn -v -i eth2 -s 1500 -c 1 ‘ether[20:2]==0x2000’ 2>/dev/null|egrep “port-ID|Address|Devices-ID|VLAN”

This command will be very useful when you trouble shoot network interface, especially when you requested new network patching for a particular vlan network

bathtub curve (product failure behaviour)

As part of build engineering team, today I got attracted to the “bathtub curve” behavior which is widely used in Reliability Engineering. Though it’s nothing specific to IT infrastructure, but this theory will help a build engineer to understand behavior of build server issues.


Linux Distro “Tails” (Safe browsing using live cd/pen drive)


If you want to browse safely without any fear of security, then try this Linux Distro “Trails”

This will be handy to browse for financial activities like accessing bank accounts, credit card transactions. I still not tried this, will give my comments once I try this.


I came to know about this Linux distro when I am reading corporate spy news, where they suggested to use live cd/pen drive of “Trails” when you are on business trip.