Debian is known for strict adherence to the Unix and free software philosophies. Debian is also known for an abundance of options — the current release includes over twenty-six thousand software packages. Today, Debian turns 15 – HAPPY BIRTHDAY!!!
Updated kernel packages that fix several bugs are now available for Debian Linux v4.0.
Havoc Pennington discovered that DBus, a simple interprocess messaging system, performs insufficient validation of security policies, which might allow local privilege escalation.
This may come handy, from the project page:
Mk-boot-usb is a perl script to create multiple-bootable usb sticks (usb keys / usb flash drives). It wipes out an entire usb stick, partitions it, creates file systems on it, installs grub, and installs a minimal linux on it. Mk-boot-usb is meant to speed up and lower the barrier of entry for creating bootable usb sticks. The usb stick will immediately become bootable (using the minimal linux), and more useful distributions can then be installed into other partitions manually simply by (1) copying any Live CD into each partition (2) modifying grub’s configuration file.
=> Mk-boot-usb: a Script to Create Multiple-Bootable USB Sticks
Related: How to Create Bootable Linux CD
My previous article related to iSCSI storage and NAS storage brought a couple of questions. An interesting question from my mail bag:
I’ve 5 Debian Linux servers with HP SAN box. Should I boot from SAN?
No, use centralized network storage for shared data or high availability configuration only. Technically you can boot and configure system. However I don’t recommend booting from SAN or any other central server until and unless you need diskless nodes:
[a] Use local storage – Always use local storage for /boot and / (root) filesystem
[b] Keep it simply – Booting from SAN volumes is complicated procedure. Most operating systems are not designed for this kind of configuration. You need to modify scripts and booting procedure.
[c] SAN booting support – Your SAN vendor must support platform booting a Linux server. You need to configure HBA and SAN according to vendor specification. You must totally depend upon SAN vendor for drivers and firmware (HBA Bios) to get thing work properly. General principle – don’t put all your eggs in one basket err one vendor 😉
[d] Other factors – Proper fiber channel topology must be used. Make sure Multipathing and redundant SAN links are used. The boot disk LUN is dedicated to a single host. etc
As you can see, complications started to increases, hence I don’t recommend booting from SAN.
Xen is a free open source software virtual machine monitor for Intel / PowerPC architectures. It is software that runs on a host operating system and allows several guest operating systems to be run on top of the host on the same computer hardware at the same time (just like VMWare software). Luckily Installing and managing XEN is quite easy under CentOS 5 Linux.
Hardware and software failures are part of life. And that is why you need to have a backup plan. I have already written about backing up files and MySQL databases. There is no need to backup all installed binaries and software programs. The following tip will not just save your time, but both Debian and RHEL based distro can be updated instantly.
Q. I want to configure modem to dial out and connect to the Internet. Since I don’t have good display card, I am not using the X window system. How do I configure (external) modem to connect to the Internet using a PPP dialup account under Debian Linux?
A. It is true that dialup modems have become almost obsolete due to broadband Internet connections, there are still situations where dialup access can prove useful 🙂
Under Linux you can dial out using program called wvdial. It is a PPP dialer with built-in intelligence. It dials a modem and starts PPP in order to connect to the Internet. The connection started with wvdial can be dropped by switching back to the terminal from where it was started and pressing ctrl-C.
The default configuration file is: /etc/wvdial.conf.
Since you are using Debian Linux, use apt-get (assuming that CDROM is your source):
# apt-get install wvdial
Other Linux distribution users can download wvdial from Internet or install from your distribution CD/DVD-ROM disk.
First, make sure modem is installed and type the following command to configure the modem:
# wvdialconf /etc/wvdial.conf
Once modem is detected you need to edit /etc/wvdial.conf configuration file to specify the PPP username, password and dial out phone number.
Modem = /dev/ttyS1
Baud = 115200
Init1 = ATZ
Phone = 172226
Username = Your-USERNAME
Password = Your-PASSWORD
Save and close the file.
To connect to internet type command:
To disconnect, switch back to the terminal from where it was started and pressing CTRL+C.
- PPP Howto (old document but contains some good stuff)
whowatch is a interactive, ncurses-based, process and users monitoring tool, which updates information in real time. This is a perfect tool for local and remote servers. With this tool you can easily answer following question:
“How do I know who are logged on in using telnet , ssh, ftp etc and what resources are they are using?”
Output of whowatch command
It displays information about the users currently logged on to the machine, in real-time. Besides standard information (login name, tty, host, user’s process), the type of the connection (ie. telnet or ssh) is shown. Display of users command line can be switch
to tty idle time. Certain user can be selected and his processes tree may be viewed as well as tree of all system processes. Tree may be displayed with additional column that shows owner of each process. In the process tree mode SIGINT and SIGKILL signals can be sent to the selected process. Killing processes is just as simple and fun as deleting lines on the screen.
How do I install whowatch tool?
If you are using Debian Linux, type the following command:
# apt-get install whowatch
If you are using FreeBSD, type the any one of the following command:
# pkg_add -r -v whowatch
You can also use ports collection under FreeBSD:
# cd /ports/sysutils/whowatch
# make; make install; make clean
ALTERNATIVELY, download from official website.
How do I use whowatch?
Simply type whowatch at command prompt:
Detailed information about process / user
Menu (press F9 key to activate menu option)
dd is a perfect tool for copy a file, converting and formatting according to the operands. dd command works on Linux and a Unix-like system whose primary job is to convert and copy files. It can create exact CD-ROM ISO image or create a new CD/DVD iso image. This is useful for making a backup, as well as for hard drive installations, require a working the use of ISO images.