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.

Recovering ASUS Fonepad 7 (K012 / FE170CG) from boot loop error

There comes a time in a tablet’s life when firmware crashes and needs recovery (due to events beyond the user’s control, of course, such as OTA updating a rooted firmware).

In such times the unwritten details (like procedures and filenames) are what separate a brick from a successful recovery.

Configure call forwarding in GSM networks

There are times one one has more phone numbers than one can handle or when one needs to make sure one can receive calls on a number even when the phone’s battery died or there is no network coverage.

This is where call forwarding comes in – where for a price (the forward is taxed as an outgoing call) incoming calls can be sent to an alternative phone number…