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High-End Linux Consulting and Security

System Administration
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Security Hotline   Security Hotline 49 (0)1724728123
  First aid for hacked   Linux servers.

Contact   Email: Norbert Klein
  Tel: 49 (0)1724728123
  ICQ: 218595557


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Services
ok SELinux administration
ok Configuration of standard daemons
ok Web server harderning
ok Analysis of compromised servers
ok Setup of LVS clusters
ok Network monitoring with Nagios and Cacti
ok Scripting: Perl, PHP, shell script, SQL, C

SLES, openSUSE, Debian
Your benefits
Instant work relief
100% knowledge transfer
Low administration effort
Locations
I work in all English and German-speaking Countries. Whereever you need my expertise, I will go there.
There is no time limit, I stay as long as needed, until job is done.

Costs
50€/hour + VAT, all-inclusive, on location
40€/hour + VAT, all-inclusive, remote
Individual agreements are possible.

Next availability
Ca. June 1, 2009

Qualifications and practical experiences
I have studied computer science in Germany. My degree is "Diplom-Informatiker(FH)" which is between bachelor and master. Additionally I am certified as a Novell CLP and CLE 10.

I have more than four years experience in professional Linux system administration.
Some of the companies I worked with are "1und1 Internet AG", "//SEIBERT/MEDIA Gmbh" and "Fox Mobile Distribution GmbH".
Latest Linux Videos

Video Tutorial for dhcpcd
How to retrieve an IP address from the command line with dhcpcd

Video Tutorial for Snort
How to test Snort with hping3


Linux Tutorials

The Weathermap Plugin of Cacti


The Discovery Plugin of Cacti


Investigation of hacked Linux Servers


Cacti Tips


snmpd binds to 127.0.0.1 only


Examples of SNMP requests


Delete a Gnome session


Change the language in Gnome


My favorite Linux books


Examples of common SELinux commands


How to make SELinux log to a seperate file


Tell SELinux to NOT log only once in permissive mode


SELinux newrole Couldn't get default type


Print the whole command line of processes with ps


How to run two independent MySQL daemons on the same server


How to burn a DVD image with growisofs and verify it


How to run two instances of sshd on Debian


mdadm error No mail address or alert command - not monitoring


How to find processes associated with open ports


How to search in the bash history


Configure Postfix as a relay client


Nagios notification commands and Postfix sendmail


NaNs in Cacti/Spine


Bash scripts for text file manipulations


PHP scripts and HTTP error 500


vBulletin installation with UTF-8


Full backup of web servers with MySQL databases


Linux Server Hardening


Nagios 3 installation tutorial for Gentoo


How to test SNORT


Use dhcpcd on the shell to retrieve an IP address via DHCP


How to change the file permissions with chmod and chown


Replace SSH login with public key authentication


A compromised web server from the hackers point of view


More security for Apache web servers with mod_security


Some tips to find out if a web server was hacked


Where do answers and solutions come from?


The monitoring server tutorial with Nagios 2.8, NRPE 2.7.1 and Fruity


Secure settings for PHP web applications in php.ini


Configure syslog-ng to store firewall logs in a separate log file


Example telnet ESMTP session with SMTP AUTH


Basic commands and tips for the text editor Vim


How to paste text into VIM with correct text indention


Mysql commands


The command mysqldump


Environment variables


How to validate a Google Sitemap


The command iptables


Running MySQL queries from a shell script or from the command line


How to create IP aliases on Linux


Gentoo configuration management with Cfengine and Subversion


How to set up a Postfix mail server with MySQL backend on Gentoo


How to rewrite the sender address in Postfix


Setting up a load balancing cluster with director failover based on Keepalived, LVS and Gentoo


Burn CDs and DVDs from the command line


Encrypting and decrypting files with GnuPG


Use screen to return to a session on a remote server even if the connection has been closed


How to configure grub for several linux installations on one hard drive


Use Allrights to backup and restore file permissions suid sgid sticky bits owners and groups


Check scripts written in Perl for the Nagios plug-in NRPE


How to create cronjobs


The command awk


The command sed


How to handle unusual file or directory names


How to use fdisk within a shell script


For loops as one-liners and within shell scripts


Control permissions of new files and directories with umask


Merging text files with a simple Perl script


Block SSH login attempts with denyhosts


How to send a message to other logged in users


Get a nice directory overview in the shell with tree


Display and set Linux kernel parameters with sysctl


The if statement in bash scripts and as a oneliner


Simple load testing of the Apache2 webserver with ab2


Create large files with random content


How to disable a Linux user account


Process examination with strace


Detecting all hosts in a network which are online


Gentoo Port for the nagios-plugins package modified for vservers


Simple example to collect system activity information with sysstat


rdate is a simple way to synchronize a hosts system time


Rotating log files which are being held by an open file descriptor


How to change the scheduling priority of CGIs


Web frontend for Apache .htaccess files


Measure the execution time of commands


Retrieve DNS information with dig


A simple web user agent in Perl


Whitelist patch for qmail ra-plugin rblchecks


How to find out the current shell type


If a root-server cannot boot the rescue system anymore


How to redirect stdin, stdout, stderr and use simple interprocess communication


Creating .htpasswd and .htaccess files from the command line


Create a nice greeting for the ssh login


Parallel execution of shell commands on several servers with DSH


How to change root within a shell script with chroot


Getting lots of information about files and file systems with stat


Gentoo tips and tricks


The internal field separator IFS


Turning off the tab-completion bell


The command split


The command cut


The command hdparm


The command tr


Perl example to get the calendar week


Use Whoisonline to analyse your web server traffic


Use Getmails to extract email addresses from Postcard Direct log files and other text files


How to find the name of the linux distribution


Use basename to get the filename from a path


The command cal


The command date


The command tar


The command find


The command grep


The command cp


The command nl


The command procinfo


The command pkill


The command pgrep


The commands kill and jobs


The command fuser


The command pstree


The command pidof


The command top


The command replace


The command chkconfig


The command xinetd


The command ifconfig


The command du


The command df


The command diff


The command scp


The command ssh


The command whereis


The command watch


The commands mount and unmount


The command cancel


The command lpstat


The command lp


The command wc


The command touch


The command rm


The command exit


The command chroot


The command uname


The command runlevel


The command su


The command finger


The command whoami


Show logins with the command last


The command w


The command passwd


The commands clear and reset


The command hostname


The command file


The commands unset and set


The commands modprobe and lsmod


The command recode


The command tail


The command head


The command pwd


The command pmap


The command wget


The command ls


The commands man and info