Μήνας: Μαΐου 2011

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Red Hat Certificate Exam Preparation

Marios asked me to elaborate a little on the Red Hat Certification Exams and my preparation.

I found the lab based exams much better than other multiple choice exams. It doesn’t matter if you do something using the command line, a gui tool, or if you write a program yourself to do the job. It’s real world simulation!

The preparation was self-study using the following:

No book covering RHEL6 existed while I was preparing, but I believe one is available now (ISBN 0321767950) and others are on their way (e.g. ISBN 0071765654).

I also recently discovered OpenRHCE by @texastwister, an effort to collaboratively prepare study materials to help candidates achieve Red Hat’s RHCE certification, under a CC license.

I found the journey of answering all the above quite a rewording experience. I have learned new things and I can definately troubleshoot SELinux issues faster than before ;-)

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IPv6 reverse DNS in 60″

Your allocation: 2001:db8/32
You LAN: 2001:db8:2:2001/64
Your device: 2001:db8:2:2001::11 (mydevice.local)

Let «host» do the dirty work for you!

sotiris@jumbo:~$ host 2001:db8:2:2001::11
Host 1.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1.0.0.2.2.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa not found: 3(NXDOMAIN)

The zone for your /32 is 8.b.d.0.1.0.0.2.ip6.arpa

$TTL 1d
@    IN    SOA ( 42 1h 15m 30d 10m )
     IN    NS    localhost.
;
1.0.0.2.2.0.0.0    IN    NS    localhost. ; delegate 2001:db8:2:2001/64

The zone for your /64 is 1.0.0.2.2.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa

$TTL 1d
@    IN    SOA ( 42 1h 15m 30d 10m )
     IN    NS    localhost.
;
1.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0 IN PTR mydevice.local.

Reconfig and run host again

sotiris@jumbo:~$ host 2001:db8:2:2001::11
1.1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1.0.0.2.2.0.0.0.8.b.d.0.1.0.0.2.ip6.arpa domain name pointer mydevice.local.