Linux Blog

How to add a module to an existing kernel

Sometime you need to add a new driver to a modular kernel, you can just compile the needed module and install it without recompiling the entire kernel. Just follow these steps:

# cd /usr/src/linux (location where linux kernel source is stored)
# make config Or make menuconfig OR make xconfig
(Choose the driver as a module)

# make dep
# make modules
# make modules_install
# depmod -a

You should now be able to use the new module.

How to do Virtual hosting in Vsftpd

There are two ways of doing this ...

1. If you integrate vsftpd with xinetd, you can use xinetd to bind to several different IP addresses. For each IP address, get xinetd to launch vsftpd with a different config file. This way, you can get different behavior per virtual address.

2. Alternatively, run as many copies as vsftpd as necessary, in standalone
mode. Use “listen_address=x.x.x.x” to set the virtual IP.

Prevent the reuse of old passwords

The PAM module pam_unix.so can be configured to maintain a list of old passwords for every user prohibiting the reuse of old passwords.

The list is located in the /etc/security/opasswd file. This is not a plain text file, but it should be protected the same as the /etc/shadow file. This is normally referred to as password history.

To remember the last 5 passwords, add the line below to the /etc/pam.d/system-auth file:

password sufficient /lib/security/pam_unix.so use_authtok md5 shadow remember=5

Install multimedia Support in Fedora 8

Follow these instructions to get mp3 and other multimedia support on your Fedora Core 8.

Open a terminal and become root, then run this command:

# wget http://livna-dl.reloumirrors.net/fedora/8/i386/livna-release-8-1.noarch.rpm
# rpm -ivh livna-release-8-1.noarch.rpm

Install all other plug ins..

# yum -y install gstreamer-plugins-bad gstreamer-plugins-ugly xine-lib-extras-nonfree

How to Encrypt - Decrypt your files

To Encrypt a normal file:
$ openssl des3 -salt -in myfile.txt -out outputfile.des3
[This will ask for password, give any pass that you can remember]

To Decrypt:
$ openssl des3 -d -salt -in outputfile.des3 -out myfile.txt -k password