How to solve Apache – Could not reliably determine the server’s fully qualified name – error in Ubuntu

Apache2 web server will almost always display this information message :
"Could not reliably determine the server's fully qualified name"
when it is first started in Ubuntu and Debian server.

The reason behind this message is because the web server fails to find the suitable domain name in the system.

How to remove the message
First, you need to edit “/etc/hosts” file and put your server name of choice in the file. For example:

127.0.0.1 server.mylocal

Then you need to add “ServerName” directive in the “/etc/apache2/apache2.conf” file.

ServerName server.mylocal

Finally, restart the web server for the changes to take effect. You will notice that the information message is gone now.

$ sudo service apache2 restart

Howto solve ssh_exchange_identification: Connection closed by remote host error

I’ve keep getting the message “ssh_exchange_identification: Connection closed by remote host error” after I managed to finalized my CRUX linux on my decTOP box today. After enough looking into documentations, I finally found out that I need to edit the “/etc/hosts.allow” file to allow SSH connection, for example:


#/etc/hosts.allow
sshd:ALL

or for more conservative setting


#/etc/hosts.allow
sshd:LOCAL
sshd:192.168.1.0/255.255.255.0

I can connect ssh to my box normally after that.

How to block ads and malware websites using /etc/hosts files in Ubuntu

Here’s an easy way to block annoying advertisement and malware sites using ‘/etc/hosts’ file.

First edit the /etc/hosts files using your favorite text editor :

sudo gedit /etc/hosts

Then, paste the list of ads/malware servers in the ‘hosts’ file. You can get the list from http://someonewhocares.org/hosts/ or by searching through Google.

Close the file, and Save. The change will take effect immediately after that. One of the side-effect from this modfication is that your web surfing experience would be significantly faster because your browser does not have to wait for the annoying advertisement to load.