Editing “message of the day” – motd

The message of the day is a nice thing to show informations to a user, who is connecting via console. You can put funny ascii figures there, or important informations and how-to’s.
The message will be shown prompltly after authentification:

Changing ssh port to improve security

For security reasons, it’s advisable to change the ssh standard port 22 into something else. So you will get less attacks to sshd. This improves the security for your server. Furthermore, you should block root from connecting via ssh.
Open your /etc/ssh/sshd_config
Changing the port:

# This is the sshd server system-wide configuration file. See sshd(8)
# for [...]

How to setup email forwarding in PLESK

With PLESK you’re able to define some email forwardings / redirects which makes your mailing more comfortable. Don’t forget to update your DNS records also (if this is in your keeping).
Step 1: login to the backend. Usually your domain with port 8443. Example:
https://www.yourdomain.com:8443

Cartoonize an image with GIMP

How to cartoonize an image? With photoshop, there are tons of tutorials outside, but with GIMP? I have found a very nice walk through:

Layer – Duplicate Layer
Select the new layer, Filters->Edge-Detect->Edge, select Sobel, Amount should be 2.0, and Black should be checked
Invert the edge-mask layer, it’s in Layers->Colors->Invert
Back in the Layers Dialog, change the Layer [...]

Scripting a firewall with iptables

IPTables is a text based frontend for the ipchains kernel module. The ipchains support is compiled into most kernels of todays distributions. With iptables you don’t have to use a graphical tool. So it’s very suitable for scritpting.
First thing to do is installing neccessary packages, for Ubuntu / Debian:
apt-get update
apt-get install iptables
When the package is [...]

WHOIS services and IP location

If you want to know, where an IP adress is located, or who has owned a domain, choose one of the links below: