Archive for August, 2008
August 30, 2008 at 2:58 pm
· Filed under Linux ·Tagged nobody, user nobody
There is some default user at Linux/Unix system. nobody is one of them. It has no login shell. That means this user can never login at the system. The user id of the nobody user is 99. and the group id is 99.
The nobody account is suppose to be used for anonymous NFS access.
From a Solaris viewpoint:
nobody – Assigned to users or software processes that do not need nor should have any special permissions. nobody is used in patch installation process, NFS, Web servers and directory services. This is an anonymous user account, assigned by an NFS server when a request is received from an unauthorized root user. NFS uses it to secure file servers on networks where diskless clients can be rebooted in single-user mode by anyone with physical access. The nobody user account is also assigned to software processes that do not need nor should have any special permissions. Some daemons, such as fingerd, run as nobody. If in.tftpd is enabled, it will run as the user nobody. Disabling this account will interfere with patching your system, NFS services as will as causing problems in other areas.
noaccess – The account that is assigned to a user or a process that needs access to a system through some application but without actually logging in.
nobody4 — SunOS 4.0 or 4.1 version of the nobody user account. The nobody4 user can actually be eliminated if you’re absolutely certain you’ll never need to use/access SunOS 4.x services. Disabling this account would interfere with communications between earlier revisions on SunOS (4.x).
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August 25, 2008 at 10:41 am
· Filed under Linux, Servers ·Tagged in linux, one pc restart momentarily
Today I get a problem “suppose in linux, one pc restart momentarily.then how do u solved it?”
My suggestion regarding this issue is as follows,
it may occur because of many issue.
1. may be hardware problem.
2. may be OS problem
3. may be configuration problem of inittab file.
If the problem is with hardware then you have to fix the hardware.
If the problem is with the OS then install a fresh OS.
If you boot your OS at run level 6 then the pc will restart momentarily. You have to change the default run level. As your pc is also restarting momenterily, you must have to log in at single user mode to change the configuration at /etc/inittab .
In my next post I shall try to discuss to change the default run-level.
Any comments regarding these issue will be highly welcome.
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August 23, 2008 at 3:52 pm
· Filed under windows ·Tagged Generic Host Process for Win32 has encountered a proble
Today I got a mail with a following problem.
I am getting this error which says “Generic Host Process for Win32 has encountered a problem and needs to close. We are sorry for inconvenience.”
After getting this error, computer acts rather scary! Internet is disconnected (BroadBand) and wont allow me to connect again until I restart my computer.
Normally this problem occurs due to installing two Antivirus at the same pc. After uninstalling one the problem gets solved.
Sometimes anti-virus and spy-ware (both are installed) cause this problem. After uninstalling one, the problem gets solved.
This occured because, Two Anti-Virus and two Anti-Spyware programs monitoring your system at the same time.
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August 12, 2008 at 3:28 pm
· Filed under Linux, Networking ·Tagged runlevel 4, why runlevel-4 didn’t use?
Today I have got this comment from one of my friend. One thing I want to clear you that, run levels are not same for all linux version. Suppose here is usage of run level 4 at different versions:
Redhat/Fedora Normally not used (user definable).
SUSE Normally not used (user definable).
Slackware Full multi-user with display manager
Gentoo Linux Aliased for runlevel 3 (Full multi-user with display manager)
System V Multi-user, user-defined
Solaris Alternative multi-user, user-defined
HP-UX Multi-user with VUE started instead of CDE
In fine we may say that in maximum cases run level 4 is user defined. Runlevel 4 is usually a “custom” level. By default it will start a few more services than level 3. This level is usually only used under special circumstances.
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August 5, 2008 at 1:27 pm
· Filed under Linux, Networking ·Tagged Clonning MAC address at LINUX
To clone a MAC address of a NIC at Linux we can use the following commands.
1. We have to get down the interface in which we are going to clone. Here we are clonning on interface eth0.
#ifdown eth0
2. Now we will add the MAC address at the interface eth0 with the following command.
#ifconfig eth0 hw ether 00:05:5B:33:A3:15
3. Now bring the interface up.
#ifup eth0
If we want to use the MAC permanently we can add the three command at /etc/rc.local file .
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August 5, 2008 at 1:20 pm
· Filed under Linux, Networking ·Tagged runlevel, runlevel at linux
There are 7 runlevels at linux. these are:
runlevel 0 –> shutdown
runlevel 1–> single user
runlevel 2–> multiuser without NFS
runlevel 3–> multiuser with NFS
runlevel 4–> normally not in use (User defined)
runlevel 5 –> Graphical user interface
runlevel 6 –> restart
We can go to any runlevel by typing init runlevel . As for example to go to graphical user mode we can type init 5. To restart we can type init 6, to shutdown init 0 etc.
The run level differs according to the OS. Suppose HP-UX, Solaris, Redhat, SUSE, Debian—– have different run level system. Redhat, SUSE, Debian are same. Others are a little different.
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August 5, 2008 at 1:14 pm
· Filed under Linux, Networking ·Tagged how to shutdown linux, howto restart linux, init 0, init 6, restart linux, shutdown linux
To shutdown we can use any of the following commands.
#init 0
#poweroff
#shutdown -h now
#shutdown -h 0
#shutdown -h 10 (will shutdown after 10 minutes)
#halt -p
To restart we can use any of the following commands:
#init 6
#reboot
#shutdown -h now
Ctrl+Alt+Delete (3 finger salute)
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August 4, 2008 at 4:49 pm
· Filed under Linux, Networking ·Tagged knoppix, password breaking at debian, root password break
Sometimes we may forget the root password. Then we need to login by breaking password. If we do not know how to break it, then we need to reinstall the OS and loose many important data. I want to share one way of breaking password at debian.
While booting you will be prompted some options like debian kernel XXX options. If you does not press any key the OS get boot on its by default type. To break the password you must stop the booting by pressing a key.
1. Then press e to edit
2. then type
boot: Linux init=/bin/sh
and press enter.
3. This will boot OS on run level 1, which wont want any password. Here you will need to mount the following things.
init-2.03# mount -n -o remount,rw /
init-2.03# mount -avt nonfs,noproc,nosmbfs
4. Now you can go to /etc and remove the password. To do so you have to remove root password from /etc/passwd and /etc/shadow. So…..
init-2.03# cd /etc
init-2.03# vi passwd
init-2.03# vi shadow
That’s all. Now restart your OS and you will find that there is no root password. After logging as root just set a new root password.
Hope to hear from you about better procedure of breaking password.
There is another way to break password using knoppix. As far as I know knoppix is also a boot loader s/w that helps us to break root password of linux. But I did not ever break password using knoppix.
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