Infos zu Linux und die Unterlagen zu den Linux-Kursen am Wifi Wien.

Putting fail2ban to good use: whitelisting SSH logins

Posted Sat, 2012-03-03 01:23 by Wolfgang Karall

I don't like fail2ban all that much (neither do I like denyhosts or other similar software, I'm really egalitarian there), because it is based on the idea of using blacklists. Which don't work. If you don't believe me and rather believe more famous people, read http://www.codinghorror.com/blog/2007/12/blacklists-dont-work.html

mysql-server while upgrading Debian 5.0 (lenny) to 6.0 (squeeze)

Posted Tue, 2012-02-21 19:11 by Wolfgang Karall

I'm currently doing plenty of upgrades to Debian 6.0 for customers who tried to wait till the last moment, after all Lenny's security support ended on 9th of February, see http://www.debian.org/News/2012/20120209

Help, ssh is eating up all my standard input!

Posted Fri, 2011-10-21 23:09 by Wolfgang Karall

If you're running ssh inside a shell script that's reading from standard input (stdin), beware that the ssh execution will drain stdin unless you use the -n option.

GRUB 2 and extending a LVM volume group

Posted Tue, 2011-04-05 21:13 by Wolfgang Karall

While installing security updates in a seldomly used virtual machine, the latest kernel package was ready to be configured when I got the following error:

Setting up linux-image-2.6.32-5-amd64 (2.6.32-31) ...
Running depmod.
Running update-initramfs.
update-initramfs: Generating /boot/initrd.img-2.6.32-5-amd64
Examining /etc/kernel/postinst.d.
run-parts: executing /etc/kernel/postinst.d/initramfs-tools 2.6.32-5-amd64 /boot/vmlinuz-2.6.32-5-amd64
run-parts: executing /etc/kernel/postinst.d/zz-update-grub 2.6.32-5-amd64 /boot/vmlinuz-2.6.32-5-amd64
Generating grub.cfg ...
/usr/sbin/grub-probe: error: Couldn't find PV pv1. Check your device.map.
run-parts: /etc/kernel/postinst.d/zz-update-grub exited with return code 1
Failed to process /etc/kernel/postinst.d at /var/lib/dpkg/info/linux-image-2.6.32-5-amd64.postinst line 799.
dpkg: error processing linux-image-2.6.32-5-amd64 (--configure):
 subprocess installed post-installation script returned error exit status 2
Errors were encountered while processing:
 linux-image-2.6.32-5-amd64

First I didn't quite get the line about "Couldn't find PV pv1. Check your device.map", but after some time it dawned on me that "PV" might mean "physical volume", a term used by LVM. I also remembered that I extended the LVM volume group with an additional block device that I attached to the virtual machine.

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