Clean up older installed kernels on CentOS

Linux generally keeps multiple versions of the kernel installed. This is done to maintain backwards stability and allow the selection of an older (tried and tested) kernel if the latest update fails in any way.

On a small system all these kernel versions can quickly add up and waste valuable space. In such case keeping only the needed versions (the latest and the one currently booted, if different) is an acceptable risk to take.

Control Apache’s public server information

By default Apache displays information about itself in the server signature included with reply headers and sometimes auto-generated pages. This information can give away important clues, like the exact version number of a module or Apache itself.

While obscurity never increases security since exploits can be attempted on the service regardless, knowing exact version information and running modules certainly provides a potential hacker with useful clues and eases the task.

How to configure IPSec/L2TP VPN server in CentOS 6

I had to look for an alternate VPN system to use when I need to dial back to my home network while on the move to access my media library or when I require a trusted connection or a whitelisted IP.

The next best thing (and least complicated to set up going from PPTP) is IPSec/L2TP, which has built-in support in most current operating systems (including Windows, Linux and Android). Due to its double-encapsulation nature (L2TP performs the tunnelling of data and IPSec provides the encrypted channel), L2TP/IPSec has a more complex setup and configuration procedure, both for the server and the client.

DVB-C TV on Raspberry PI with LibreELEC/Kodi

There are plenty of TVs to chose from and nowadays they all know DVB-C so why go through all the trouble of building a TV player with a Raspberry PI?

Well… because it’s fun and because of the freedom of being able to watch your favourite TV channel on any of your devices – even when away.

Automatically restart Webmin/Virtualmin in case of failure

Running out of memory sometimes happens on swap-less VPSes, and it seems Webmin (together with its twin, Virtualmin) are among the first processes to die in out-of-memory cases.

Setting up a little script to check for and restart Webmin if it is no longer running is a pretty simple (workaround) solution – but should never replace the proper procedure of adjusting the settings or upgrading the VPS to avoid running out of memory in the future.

Directory listing failed in FileZilla with ProFTPd on Virtualmin

Everything appears normal in the FTP server’s log:
fr01-srv proftpd[5591]: 192.168.0.1 – USER testuser: Login successful.

However, in Filezilla things are different:
Error: Connection timed out after 20 seconds of inactivity Error: Failed to retrieve directory listing