Understanding File Permissions:
There are a number of file permissions, which can be used
for a variety of different purposes, however we'll limit
this tutorial to the ones most commonly used.
To begin with, it's important you understand the three
categories of permissions, which are:
Owner Permissions:
The owner is you. In most cases, this is not so much of a
concern, as you can only obtain owner permissions in one
of two ways.
1. FTP into your account using your Username and
Password.
2. Login via Telnet with the same information.
Group Permissions:
The represents a group of users who have access to a
particular directory. For example, a password protected
directory, whereas only members can access it upon
providing the correct Username and Password. In this case,
any permissions you assign to "Group" would be applicable
to users with access to that particular directory.
Public Permissions:
This is the most important one of all. Public permissions
determine what your world wide visitors can and cannot do
with your files. ALWAYS make sure you understand what a
particular permission does before assigning it to a file.
If not, you may wakeup to find your website demolished by
some clown who was snooping about and gained access to
your files.
Setting File Permissions:
How To Set Permissions
There are three different ways to set permissions for
your files and directories within your account.
1) File Manager,
2) FTP, and
3) Telnet.
We DO NOT encourage
the use of Telnet if
it is only being used for setting permissions and will
forego its explanation here.
Setting Permissions Using Your
File Manager
Log into your control panel and then click on "file
manager."
You will now see a list of directories within the root
of your account. Since all of your html files and
subdirectories are uploaded and created within your
public_html directory, you need to click on the file
folder next to the public-html directory name.
The directory will open and in the upper right hand
corner, there will be a list of actions that you can
perform for that directory. Next click on the file
icon located next to the text name of the file that you
want to change permissions for.
Again, in the upper right hand corner you will see a
list of actions that you can perform with this file.
Simply click on Change Permissions, select the appropriate
permissions and save.
Setting Permissions using
Fetch for MAC:
If you have Fetch for the Mac, you have an easy way to
change permissions.
Go to the file you want to change the permissions on,
and highlight it. Under the Remote menu, select Change
Permissions.
A window will pop up showing the current permissions
for the file you had highlighted. Click on the boxes to
change permissions as needed.
Setting Permissions Using
WS_FTP for Windows:
WS_FTP accomplishes the same task as above.
Just highlight the file you want to check, and
right-click on it.
A menu will pop up, then select CHMOD.
Click on the appropriate settings as needed.

When setting permissions for cgi scripts, the most common
permissions setting is 755.
755 allows the owner "Read and Write"
access, while allowing the Group and Public "Read and
Execute" permissions.
So what are we actually saying? In short,
when users access your cgi script, the server has been
instructed to grant them permissions to "Read and Execute"
it.
Sound scary? It's not actually…
Remember that a script is a program that must be processed
by the server. As long as the script is written properly,
you can safely allow users to execute it, and thus
providing the desired results.
For example, if they wanted to post a
message to your wwwboard discussion forum, then they would
need these permissions to execute wwwboard.pl, which would
write their new message to an html file, which is
displayed on the main forum.
The new message would reside in a
directory on your site so other users could view it.
Most cgi, perl
and other scripts you'll be installing come complete with
instructions telling you which permissions you'll need to
set them to.
WARNING!
Setting permissions on files is a relatively simple task,
however MAKE SURE you fully understand what it is you're
allowing the public to do with your files.
For example, some less experienced users
often make the fatal mistake of simply setting ALL of
their files to 777.
While 777 will automatically allow
executing privileges, it also allows full "READ, WRITE,
and EXECUTION ability to the entire world!!!!
This is how web sites get hacked! While most visitors have
good intentions, all it takes is one person whom snoops
about your files seeking an "Open Back Door."
This could result is them gaining full
access to your directories, which means they can do
anything from deleting your entire site, to defacing it
with obscenities.
New to cgi? Here is a page with questions and answers to
numerous questions evolving around the inns and outs of
using cgi within your scripts:
http://www.w3.org/Security/Faq/www-security-faq.ht