Preparation:
! Important: Back up the system in any case before the upgrade! If it is a virtual machine, best copy the entire VM or create snapshot. In dedicated systems at least the following directories: "/ etc", "/ var / lib / dpkg", "/ var / lib / apt / extended_states" and save the list from the command "dpkg-get-selections"
Currently installed Debian Lenny Release:
cat / etc / debian_version <br /> 5.0.8 Before we apply the new squeeze packets in reception, all packages currently installed are brought up to date.
apt-get update apt-get upgrade <br /> <br /> apt-get dist-upgrade If the upgrade, the error message "The following packages have been kept back" appears, proceed as follows:
The message "The following packages have been kept back" means that the pacts were retained and there are newer versions of the packages listed, but which can not be installed for some reason. (Not filled or amended or new dependencies). This can be solved with the following command:
apt-get dist-upgrade-u Enter the new package mirrors:
We change the sources.list file that your in the default / etc / apt / place.
This file can you edit with your favorite editor. Personally I use here the "vi".
vi / etc / apt / sources.list Now the word "lenny" is rewritten to "squeeze" just about anywhere.
The result should look as follows:
deb http://ftp.at.debian.org/debian/ squeeze main deb-src http://ftp.at.debian.org/debian/ squeeze main
deb http://security.debian.org/ squeeze / updates main deb-src http://security.debian.org/ squeeze / updates main
Upgrading:
Download the new package lists:
apt-get update Package manager apt, dpkg and aptitude update:
apt-get install apt dpkg aptitude Update the other packages:
apt-get dist-upgrade Note: The Updatevogang can vary depending on installed components take some time and some input fields (Grbu2 parameters, services remaining species, etc) open, which can actually always be confirmed by default.
After the upgrade:
Show Debian version (result should be 6.0):
cat / etc / debian_version <br /> 6.0 Server reboot:
reboot After the server is restarted, the syslog should definitely be checked for errors:
cat / var / log / syslog It is also recommended to check the open ports:
netstat-tulpn 
