small brain dump and more

To have idea whats going on with internal-sftp when you have chrooted users, this is the way how to enable logging for internal-sftp for RedHat 7 or CentOS 7.

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As UTF8 encoding is by default installed/enabled in RedHat Enterprise Linux 6.5 / CentOS and similar distros, it drives me mad to have weird line characters in terminal when I logged in via SecureCRT/Putty due UTF-8 encoding. Read more…

Proper way of disabling IPv6 subsytem in RedHat Linux 6 / CentOS 6 (dont unload modules or so)

in /etc/sysctl.conf  :  net.ipv6.conf.all.disable_ipv6 = 1

in /etc/sysconfig/network  : NETWORKING_IPV6=no

in /etc/sysconfig/network-scripts/ifcfg-eth0 : IPV6INIT=”no”

disable iptables6 – chkconfig –level 345 ip6tables off

reboot

done 😉

PS: if you have more eth interfaces, use brain 😉

just summary 😉

1. fill with zeros empty space in runing VM OS
2. Windows – SDelete from Sysinternal LINK
3. Linux – fill up each mount point/partition with command

   dd if=/dev/zero of=ZEROFILE bs=1000000 ; rm -f ZEROFILE

   
   

4. Check real size of allocated data in VM
   

   du -h MyVM.vmdk

   
   

5. From ESX shell , run command to shrink vmdk disk (shutdown VM first)

   vmkfstools --punchzero MyVM.vmdk

6. Check real size of allocated data in VM after (should be less)
   

   du -h MyVM.vmdk

   
   

7. log off
8. If not Thin provisioned disk, use another post 😉

So,  in previous article I cleanup Linux virtual machine , zeroed all empty space. Thick file is 42 GB, lets see how it big I can make it.

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I have thick provisioned server, and I need move it and shrink it. As Thick option provides flat file of full size , even if OS is few GB, I have full size vmdk file ;( which is harder to copy around.  Thin provisioned vmdk disk is possible shrink via ESX shell command ( vmkfstools –punchzero *.vmdk) but what to do if disk is in Thick state ? Its possible, but little bit more complicated.

Excellent post to explain in depth dafuq – http://blogs.vmware.com/vsphere/2012/03/thin-provisioning-whats-the-scoop.html

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Trying brute force login to Dovecot IMAP server is happenning, log is filling up ;(

Lets block it 😉

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When you need to have proxy connection available to whole system, so dont bother with settings for firefox, yum proxy and similar, its simple as just plain file 😉

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Some collection on various find tasks I experienced from time to time. Find is powerfull tool, often overlooked, but its lifesaver. Enjoy, if you have something more, please, share in comments.

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I needed sometimes to grant access to web root for developer/friends and don’t want to  allow them “chillout” thru directories . Here is sample how to setup SSHD server to allow sftp connection and chroot it to home directory – basically lock user via SFTP to Virtual Home for web server.

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