Wednesday, March 18, 2009

RHCE TIPS - Sitting the test



SECTION I: TROUBLESHOOTING AND SYSTEM MAINTENANCE [Morning Session]
This section is easy and the proctor will let you know the result immediately.

- Compulsory Section I: It tests system maintenance, It counts for 80, which is enough for RHCE. So if you have got 80 here, you don’t need to take next non-compulsory question.
- Non-compulsory Section I: It tests system booting issue, It counts for 20. If you didn’t complete compulsory section or just after perfect sore 100, take the non-compulsory question. The proctor will re-image your PC to introduce the booting issue, So you can’t go back, once you have made the decision. You should be safe , once you have mastered all scenarios in
my previous post.

SECTION II: INSTALLATION AND CONFIGURATION [Afternoon Session]
If you have breezed through SECTION I, Don’t be too joyful, the hardest part is here.
It is hard because the time is limited, there are many tasks to complete, if you stuck with one, time is quickly running out. Secondly, no one will verify the result, you have to check by yourself. It is quite tricky, if you misinterpret the requirement, your check method maybe wrong, or service lost function after reboot.

A few tips during the test:
- TIME:
Manage well the time, don’t stuck with one question too long, you don’t need full score to pass RHCE.
- CHECK:

Check the result immediately after complete a task. Don’t expect to check everything at last, you can login to remote Linux to verify your result.

#User and file permission:
‘su – username’ to check permissions creating/listing file
#HTTP:
curl http://ServerName-or-IPAddress or elinks http://server
#Squid
curl –x proxyip:port url
#Send mail:
echo "test" mail –s "subject" user
# Send mail with specific sender:
telnet server 25 \n; mail from: user@x \n; rcpt to: user@y \n;data \n; subject: "subject x" \n; "text body "\n; .
#Receive local email:
mail or mail –f mailbox-filename
#Receive remote email:
mutt –f pop://server or mutt –f imap://server
#samba
smbclient //ip/share -U username /* Because you may not able to access the share ,even smbclient -L IP –U show the share*/
#test firewall
nc -z IP 1-200 /*scan remote hosts opening ports */
nc -v IP 25 or telnet IP 25 /* check availability of 1 port */

- Security tasks:
RHCE tasks are about restricting access for services, There are many options to achieve the result, It is up to you which one to use. Service’s native support, PAM, tcp-wrapper, iptables. Be careful using iptables, you should use open firewall which means accepting everything except specifically denied. You don’t want your firewall deny the services completed earlier.

- Need help?
Unfortunately, you don’t have internet access during test. You can only rely on the local man pages and documents. So during the preparation of the test, avoid finding the answers from internet straight away, try the local man pages and docs first. For example if you forget the format for ifcfg-ethx.cfg, the syntax is documented here:
/usr/share/doc/initscripts-XXX-/sysconfig.txt

- Lastly:
In the last mins, you should reboot your PC, check the services are still running after reboot. As pre-caution, always begin with task with this command chkconfig svcname on




2 comments:

  1. Thanks for your tips esp for RHCE.
    I am preparing for the RHCE.
    By the way congrat on your RHCE also!

    Amir

    ReplyDelete
  2. "if you misinterpret the requirement", could you
    please elaborate.

    Thanks,
    Amir

    ReplyDelete