If you want to test your RHCE knowledge, I have created a small quiz (it requires 5 minutes).
It will not replace the real exam but will check some critical points.
This way, you will remember them!

Some questions come regularly in Linux certifications forums:
Do I need to set up iptables configuration or not ?
In fact, it depends on the questions and the risk you want to take.
If there is no mention of ports in the exam and risk doesn’t frighten you, you can go for: # iptables -F; service iptables save
Otherwise, you have to learn the ports associated with each service.
During your training session, you can test your configuration in your lab with a port scanner: nmap is your friend!
# yum install -y nmap
Then, you can test your local port configuration (tcp & udp) with the following command (s for scan, T for tcp and U for udp): # nmap -sT -sU localhost
Once you’ve got your iptables configuration set up, you can test it from another VM or your KVM host. It’s simple with tcp ports: # nmap -sT myvm
Things become trickier with udp ports. If you don’t want to spend around 18 minutes to get the answer (test it if you think I’m kidding!), you have to specify the ports that you want to test: # nmap -sU -pU:53,111 myvm
It’s even possible to combine the two tests in one: # nmap -sT -sU -pT:*,U:53,111 myvm

I’m pretty sure these little tips will help you even after the exams!

For those who are about to start their preparation for the RHCSA & RHCE exams, they need to think about creating a lab. This is not an easy task because you have to know various topics to do so.
To make things easier, have a look at this lab installation guide.

When you are working in your lab, you regularly need to reinstall your virtual machine to start a new configuration.
If you use a tool like Virtual Box, you can save virtual machine images and restore them.
But if you use KVM, you can’t do that, and it takes time to reinstall the system.
To avoid this waste of time, you can set up your virtual machine inside a unique volume group (here vg_root with at least 1GB of free space) and use the snapshot feature available since RHEL6. This way, you only need to reboot and wait one or two minutes (the time for the snapshot to be restored).

The command is called snap and takes one parameter:
– begin: to start the snapshot,
– rollback: to destroy the snapshot and remove all the previous changes,
– commit: to destroy the snapshot and keep the changes.

#!/bin/sh
if [ "$#" -ne "1" ]; then
echo "Syntaxe: snap [begin|commit|rollback]"
exit
fi

case $1 in
begin) lvcreate --size 1G -s --name lv_snap /dev/vg_root/lv_root ;;
commit) lvremove -f /dev/vg_root/lv_snap ;;
rollback) lvconvert --merge /dev/vg_root/lv_snap ;;
esac

If you are really serious about taking the RHCSA exam, you should have a look to this RHCSA sample exam.
It should be a good start for your ultimate preparation.

Some people are wondering if it is still the right time to take RHEL6 exams with the future release of RHEL7.
RHEL7 shouldn’t be released before the end of Q1 2014 and certainly later according to Red Hat representatives. RHCSA & RHCE Exams are planned at least until Friday, the 27th of June 2014 in the US and until August in some other countries (see Red Hat website).
This gives more than 8 months to pass the two exams.
Also, in many companies, RHEL6 only starts to be deployed which demonstrates that RHEL6 certifications are definitely relevant.