PC Plus HelpDesk - issue 223
This month, Paul Grosse gives you more insight into
some of the topics dealt with in HelpDesk and HelpDesk
Extra
From the pages of HelpDesk, we look at:
- Origami Webcam Cover;
- Windows SMB shares in GNU/Linux;
- GNU/Linux Samba (SMB) shares in Windows; and,
- Find your real IP address.
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HelpDesk
Origami Webcam Cover
 If you have kids,
their browsing habits (running scripts and so on) might
lead to spyware being installed and executed
automatically on your computer. If you have a local
network, it might be that for someone in your house (or
office) the same situation could exist. Some spyware can
be configured to activate your webcam and either take
images at regular intervals or continuously.
To combat this, you can either unplug your webcam
every time your teenage daughter leaves it to go and do a
few more pages (or lines) of homework (and get moaned at
both by her when she comes back and the system which has
to detect it again and set up all of the drivers and so
on each time it is plugged in) or you can cover up the
camera. If you just put a piece of paper in front of it,
this can get knocked off and so on. The origami webcam
cover therefore is your ideal solution and here is how to
make it.
First of all, origami is just paper folding whereas
this includes one cut with the scissors but that is after
all of the origami has been done so please don't flame
me. Secondly, for those who know origami, I'll cut to the
chase - this is just a water bomb with the end cut off.
For everybody else...
| 1 |
 First
of all, you need to have a square sheet of paper.
In origami, this is usually coloured on one side
and white on the other.The size is important
because the box that we are going to end up
making will be one quarter of the size of the
side length so, for the commonly available
6" square origami paper, we will end up with
a box with an edge of 1.5". The hole we will
end up with in the bottom - the hole through
which we will put the end of the webcam - has to
be smaller than this but not too small. Once you
have made one, you can cut down a piece of paper
to make the box the size you want it. If you want
to make it to cover one of those sphere-type
'eyes' that sit on top of your monitor, you might
want to choose a larger piece of paper.
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| 2 |
 With
the white side facing upwards, make a fold so
that one corner goes over to its opposite corner.
Take care to make sure that folds are accurate
and sharp - run your finger nail along the fold.Also,
it is a good idea to do this on a flat surface,
at least to start with as curved or uneven
surfaces can make your folds go wrong.
|
| 3 |
 Now
open it out again and create a fold at right
angles to that by folding the other pair of
corners over to meet each other.Open it out
again and you should have a square of paper with
two diagonal folds that face the same way,
concave side to the white side.
|
| 4 |
 With
the coloured face on the inside, fold the paper
so that two opposite edges meet.Then, open it
out again.
|
| 5 |
 Repeat
with the other two edges, opening out again after
you have made the fold.You now have a piece of
paper with four folds in it, two facing one way
and two facing the other.
|
| 6 |
 If
you push the white centre-face in so that it
becomes concave, the diagonals will fold down and
the other folds will fold up, producing a
triangular shape. If you have produced a diamond
shape, you have done something wrong and you can
either force the folds the other way or make a
frog out of it.Next, fold one of the corners
up so that its point touches the apex of the
triangle. Here, we are folding one on the right,
forwards, along the yellow line so that its tip
touches the apex.
|
| 7 |
 Now
repeat with the corner on the left, folding
towards you so that you end up with a mirror
image of the one on the right that we have just
done. |
| 8 |
 It
should now look like this.Turn it over and do
the same on the other side.
|
| 9 |
 Now,
fold in the corners to the medial line that we
have been forming.Make sure that the tip of
the corner falls on an imaginary line that runs
between the two opposite corners - this should
make the fold run parallel with the medial line.
|
| 10 |
 Repeat
this with the opposite corner. |
| 11 |
 It
should now look like this. |
| 12 |
 Turn
it over and do the same to the opposite side.When
you have finished, it should look like this.
|
| 13 |
 Take
one of the loose tips and fold it down so that
the tip's medial edge lies along the medial edge
of the rest of the tip that it is being folded
down onto. The yellow, fold-line is at 90 degrees
to that medial edge.Take care to leave a small
gap of between 0.5mm and 1mm between the already
folded edge of the tip and the piece that sticks
out that we folded in on stage 9. You will see
why in a minute.
|
| 14 |
 Now,
fold the folded tip over again, but so that it's
fold goes from the centre, to the corner -
following the yellow line. |
| 15 |
 Like
so. |
| 16 |
 Now,
we need to stuff the flap we have created in
steps 13 and 14, into the fold that we made in
step 9.This should fold in flat which is why
we left the small gap in step 13.
|
| 17 |
 Now
repeat steps 13 to 16 for the other three tips. |
| 18 |
 Next,
we need to create the creases that will allow the
gussets we have made to open up when we turn it
into a cube. These will be made along the yellow
lines. |
| 19 |
   Fold
the end over, along the yellow line in step 18.
Then, fold the other end over. Next fold them the
other way.If you take care to do this neatly,
you can make quite a good job of it. Finally,
fold the origami piece flat again.
|
| 20 |
 It
is now time to violate the laws of origami and
get out the scissors.We are going to cut a
line at the open end. If you were making a water
bomb, you would put this opening up to your mouth
and blow in it, inflating the bomb. Then, you
would fill it with water and throw it at somebody
but we are not going to do that. Are we?
The hole we are going to make has to be large
enough to allow us to put the cover over the web
cam. So, having made your measurements, make your
cut half of the aperture size from the apex of
the origami piece.
|
| 21 |
 Next,
put your finger inside and pull out the shape,
working your way around, making the creases sharp
and straight. |
| 22 |
 Finally,
we have our box, ready to put over the webcam. |
| 23 |
And,
here it is, in action. |
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Windows SMB shares in GNU/Linux
Windows uses a system for file and printer resource
sharing called SMB. In GNU/Linux, the process is called
Samba. Each machine needs to have an SMB server for other
machines to see its resources and an SMB client for it to
see the resources on other machines.
In Windows, you just need to set up file and print
sharing and all is done. In Linux, you need to configure
and start the services. Although this sounds like it is a
bit more of a hassle in Linux, you only need to make sure
the configuration files have the correct information and
you have the right services running. This is done using a
text editor such as KWrite instead of working yourself
through a maze of silly wizards.
First of all, you need to get Linux to recognise the
SMB shares. To do this, you need to run smbfs which can
be done in the list in the Runlevel Editor in the Control
Centre in YaST2.
To view SMB shares in Linux, you can do one (or both)
of two things:
| 1 |
Mount the file shares in your
file system somewhere using /etc/fstab. If you
open up your fstab file, you should have
something full of lines that look a bit like...
/dev/hda3 / reiserfs defaults 1 1
/dev/hda1 /boot reiserfs defaults 1 2
They are of the general form:
Mount something,
somewhere,
somehow.
In the first case, mount the first partition
of the first hard drive (/dev/hda1) at the root
(/) using the file system reiserfs. Following
this are some parameters that tell the system
what to do. The last two numbers tell the system
whether they need checking on bootup. In the case
of the CDROM, it would not be feasible to check
that at bootup so it has 0 0
/dev/cdrom /media/cdrom auto ro,noauto,user,exec 0 0
To this, incorporate our SMB shares into the
file system, we need to create a mount point for
each. Again, Linux is all about choice so you can
mount them in the /mnt directory or, if you have
a lot of shares from all over your LAN, it would
make sense (in terms of being organised) for them
to have a directory of their own - perhaps called
/lan. In /lan, we can create more directories -
one for each machine on the LAN. Say, on our GEM
network, we have three machines with shares
called 'lapis', 'quartz' and 'zircon'. On lapis
we have a share (called 'sales') that we want to
incorporate into the server so that documents in
that share can be pulled across the network on
demand. In the others, we have some other shares.
The lines in the /etc/fstab might look like
this...
//lapis/sales /srv/www/htdocs/sales smbfs gid=100,workgroup=gem,rw,guest 0 0
//lapis/workpics /lan/lapis/wpics smbfs gid=100,workgroup=gem,rw,guest 0 0
//lapis/homepics /lan/lapis/hpics smbfs gid=100,workgroup=gem,rw,guest 0 0
//quartz/letters /lan/quartz/ltrs smbfs gid=100,workgroup=gem,rw,guest 0 0
//zircon/sat /lan/zircon/sat smbfs gid=100,workgroup=gem,rw,guest 0 0
Note that, as in the case of the second line,
the mount point does not need to have the same
name as the file share - here, 'workpics' being
mounted as 'wpics' and so on.
If you go into InfoCentre, and select 'Storage
Devices', you can see the file shares and you can
mount them by clicking on the relevant line in
the right pane and selecting 'Mount Device'.
With the share mounted in your file system,
you can access the files as though they were on
the same machine. You can make them mount at boot
time by editing the information at the end of the
line but if you have a machine that is not
online, this can slow down the boot process as
the system waits for the connections to the other
machines to time-out.
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| 2 |
Use the smb:// KIOSlave (this
was discussed in PC Plus HelpDesk issue 214). With
the smb KIOSlave installed (use YaST2 to install
this), you can open up Konqueror and in the
address line, instead of typing http://, just
type smb://. In the case of the above network,
you might get away with smb:/gem/lapis/ which
will open up an ftp style display in the window
showing the shares with their share names (even
if you have mounted them with different system
names) and any that you have not mounted as well.
So, if, in addition to the shares above, you have
one called letters, you will get...
homepics
letters
sales
workpics
Instead of typing smb:/gem/[share]/, you can
type smb://[share]/ if you are on the same
workgroup.
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GNU/Linux Samba (SMB) shares in Windows
This allows you to see directories and files (and
printers if you want) on Windows machines on the LAN.
To get this working, you need to have the smb daemon
and the nmb daemon running (you can check this in the
runlevel editor in YaST2).
Open up the file /etc/samba/smb.conf in KWrite and at
the bottom of the file, include the shares you want.
The following is an example (on a machine called
'opal') that allows read/write access (and is belt and
braces as far as use of names goes so it should work with
most versions) but you can limit this once you have got
it working - details are in the man pages for smb.conf
[NetStore]
comment = Network Addressable Storage
path = /nas/cache
public = yes
guest ok = yes
create mask = 0777
directory mask = 0777
read only = no
writable = yes
locking = no
This creates a share from the Linux machine (from a
directory called '/nas/cache') that in a Windows machine
appears in the network file structure as opal\NetStore\
that the user can read from and write to.
Use the mask numbers to limit access - this was
discussed in HelpDesk PC Plus issue 213.
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Find your real IP address
Many websites claim to be able to tell you your IP
address but unfortunately, all they can tell you is the
IP address of the proxy server that your ISP routes all
of your Internet traffic through. This is simply because
that is all that the website's webserver has been told to
look for.
If you search Google using ip address (http://www.google.com/) then look at the
sites with 'my IP address' or 'what's your
IP address' or similar, you will get a variety of IP
addresses (look at just the last number in the address as
it is likely that the first three will be the same in
each case. This should happen unless you happen not to go
through a proxy (or your ISP only uses one proxy server).
To find your IP address, so that your friends can look
at your web server or whatever service you wish to
provide, you can go to http://checkip.dyndns.org/
where they have sorted out the problem.
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