SSH Tunnels: Bypass (Almost) Any Firewall

Ever wanted to access some service like e-mail or instant messaging from your computer only to find out that it is not available within your restricted network? Not anymore. The article presents the most popular scenarios of using SSH tunneling to bypass numerous firewall rules like port blocking, proxies and more.

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Why Is Linux Successful?

The success of Linux over the past 15 years boils down to a few key factors, according to a panel of Linux luminaries.

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HOW-TO watch YOUTUBE videos from LINUX Shell Prompt

Publishing your own video on YouTube, or watching other people
�s videos, is all the rage these days. Why are we talking about YouTube, in a column about the CLI? Because this week we�re writing about youtube-dl, a clever little CLI tool that�s easy to install and and use to fetch YouTube videos.

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Monolith Media Center brings MythTV to the technophobe

If MythTV's promise of a free Windows Media Center alternative sounds exciting, but you can't quite bring yourself to navigate the trials of a Linux install on your own, then you might be interested in Monolith's pre-built Media Center PCs, which come with MythTV pre-installed on top of Ubuntu Linux. Models start at $650, and include a remote, an IRBlaster, and free electronic programming guide access -- none of those silly TiVo-style monthly fees. Specs range from a single analog tuner to dual HDTV tuners, and you can get a 400GB HDD and DVD burner as well. The 3.2GHz P4 CPU isn't exactly cutting edge, but all the same, the Monolith box should be fine for someone who doesn't want to mess with setup, and isn't afraid to spend a bit more than they would otherwise.

Read more at www.engadget.com/2006/0...

Why your IT Department Hate Macs.

The answer is: they don't. Corporations avoid Mac's not because they are hopelessly naive but because they don't know how to work with anything other than M$ Windows. Most don't know how to run a Mac or Linux.

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Linux quick notes

chmod

to change access mode of a file (file permissions)

u = the user who owns the file

g = the group the file belongs to

o = others

a = all of the above (ab abbreviation for ugo)

example: to prevent outsiders from executing archive.sh before : -rwxr-xr-x archive.sh

command: chmod o=r archive.sh

after : -rwxr-xr-- archive.sh

example : to take away all permissions for the group for topsecret.inf, leave the permissions part of the command empty.

Before : -rw-r----- topsecret.inf

command : chmod g= topsecret.inf

after : -rw------- topsecret.inf

example:

chmod go=rx wordmatic.txt

chmod go-w wordmatic.txt

chmod a+wx calcmatic.bak

To kill non responding application:

ctrl-alt-Esc

move or rename files:

mv

whatis

information on a topic

makewhatis

creates an updated whatis database

umask

the default permission given to new files created

suid and sgid

special permissions given to program so when it runs by a user, it inherits the rights of the owner of the pprogram, not the user running it.

eg. /etc/passwd

setting & removing suid & sgid

for eg.:

# chmod u+s /usr/bin/myapp

# chmod g-s /home/drobbins

Directory permissions:

Directory permissions are a bit different that file permissions.

For a directory, if the “read” (r)flag is set, you may list the contents of the directory.

“write” (w) means you may create files in the directory; and “execute” (x) means you may enter the directory and access any sub-directory inside.

Without the “execute” (x) flag, the filesystem objects inside the directory aren't accessible.

Without the “read” ( r ) flag, the filesystem objects inside the directory aren't viewable but can still be accessible as long as someone knows the full path to the object.

If a directory has the “sgid” flan enabled, any filesystem objects created inside it will inherit the group of the directory. This particular feature come in handy when you need to create a directory tree to be used by a group of people that all belong to the same group.

simply do this:

# mkdir /home/groupspace

# chgrp mygroup /home/groupspace

#chmod g+s /home/groupspace

now any users in the group mygroup can creat files or directories inside /home/groupspace, and they will be automatically assigned a group ownership if mygroup as well. Depending on the users' umask settings, new filesystem objects may or may not be readable, writable, or executable by other members of th mygroup group.

after installing Windows server 2003 on an available partition, the previous grub was destroyed from from MBR by Windows.

solution:

restart from rescue cd

reinstall grub: /sbin/grub-install /dev/hda

symbolic link:

ln -s [target] [link_name]

rsync

eg.:

rsync -av –delete /home/user/ username@server:/backup/home/user

If a directory is being backed up, remember to use / at the end of the directory name.

rsync uses ssh

Users & Groups

newgrp

useradd

groupadd

usermod

userdel -r (-r to remove user home directory too)

groupdel

ACL

acl shou be in the /etc/fstab

# getfacl

# setfacl

VNC

start vnc server:

vncserver

change password:

vncpasswd

connect to server from client by specifying the ip address/hostname and desktop

eg.:

192.168.123.10:1

configuration file:

.vnc/xstartup

default window manager is TWM, you can change it

eg.:

startkde or startgnome

to kill vnc:

vncserver -kill :1

default vnc viewer port: 5901

Java based viewer: 5801

The Downside of Certification

The worst things that ever happened to IT were Microsoft and certifications.

Off course we all know about the damage Microsoft is doing to the industry. But there is something else they or others had done that let an uneducated workforce into the industry.

Certifications are not a replacement for good education and if anything, MCSE is an indication of incompetence. I never met one how is pasionate or eager about the industry and most of them are clueless about other operating systems.

On the other hand, Linux skills are an indication of talent, motivation to develop your career and quick learners.

What are those worthless certifications good for?

Read more at www.eweek.com/article2/...