Archives for posts tagged ‘Linux’

IPTables Passive FTP Connection Tracking on non-standard ports

Ever tried to run a Linux FTP Server behind a IPTables firwall on non-standard ports, i.e. not on port 21? The problem is that the FTP connection tracking module nf_conntrack_ftp only watches port 21. If you want to use other ports the module must be loaded with the parameter “ports=21,5367″ if you want to run […]

VBoxAdm – Management-GUI for Postfix and Dovecot

Last weekend I’ve released a new web-based management GUI for Mailservers running Postfix and Dovecot. It is called VBoxAdm. Its features: All-in-one mailserver solution written in Perl (despite some tiny bits of PHP for the Roundcube integration) MySQL Backend Sane Database schema, w/ normalized tables Roundcube integration which allows users to change their vacation messages […]

Resize a Xen disk image

Its as easy as appending zeros to the disk image. Here I append 10 GB to disk.img. Please note that resize2fs will, of course, only work if your disk contains a ext2/3 partition. cd /var/lib/xend/domains/domain/ dd if=/dev/zero bs=1024 count=10000000 >> disk.img resize2fs -f disk.img Its as easy as appending zeros to the disk image. Here […]

Perl Best Practices

Recently I’ve read a really interesting book. A book every perl developer should read. At least have a look at Appendix B which lists all guidelines in a brief summary. Recently I’ve read a really interesting book. A book every perl developer should read. At least have a look at Appendix B which lists all […]

Threads in Perl are broken

Ok, for most experienced perl programmers this is not new, but let me repeat it: Threads in Perl are broken. Really, really, severe broken. Do not use threads with Perl. Thread async is probably ok for smaller computations but for anything else use fork(). Not only are IPC-Signals really dangerous with threads and DBI can’t […]

virt-manager: Error starting domain

Using KVM/virt-manager in Debian sid is interesing. You’ll get nice and fresh errors from time to time. KVM is constantly improving but you have to deal with unexpected changes from time to time which tend to break existing VMs. With the latest version I’ve got this error: Error starting domain: internal error unable to reserve […]

KDE4.4: Getting rid of Akonadi-MySQL Startup Errors

Since upgrading to KDE4.4 I’ve got startup errors each time Akonadi was started due to some missing MySQL system tables. It’s easy to fix this: akonadictl stop mysql_install_db –datadir=$HOME/.local/share/akonadi/db_data akonadictl start And don’t forget to install akonadi-kde-resource-googledata. Thanks to Trumpton. Since upgrading to KDE4.4 I’ve got startup errors each time Akonadi was started due to […]

udev Notes

udevinfo was renamed to/replaced by udevadm in Debian sid. Must tutorials still refer to udevinfo. A udev rule that works on sid w/o warnings would be something like this for a garmin gps device: # cat /etc/udev/rules.d/51-garmin.rules ATTR{idVendor}==”091e”, ATTR{idProduct}==”0003″, MODE=”666″, SYMLINK+=”GarminGPS” udevinfo was renamed to/replaced by udevadm in Debian sid. Must tutorials still refer to […]

Voyage Linux on an ALIX.2D13

I’ve just spent far too much time trying to install voyage linux on my new ALIX.2D13. Everything was fine, the only problem was that I did try to use GRUB and that wasn’t working. After changing to LILO it works like a charm. The problem is probably caused by a huge version gap between etch […]

DS18S20: CRC Error

I just got me some DS18S20 (1-wire Temperature sensors) and a DS2940 (1-wire to USB adapter). The first two did work like a charm, but the third one gave me CRC errors. CRC Failed. CRC is 63 instead of 0x00 The reason was just that, after running the first two for a while, I did […]