About web home pages

About the home pages

Most of the official Maths website content is now hosted on the central college web servers and is accessed through the URL http://www.imperial.ac.uk/mathematics with the old-style Maths website URL http://www.ma.ic.ac.uk also available. but by changing the 'www' to 'wwwf' and appending a forward slash, a tilde and a Maths username to this URL, personal home pages for that user can also be served if they exist in a special folder in that user's ICNFS home directory as in this example http://wwwf.ma.ic.ac.uk/~cb.

How do I set up my home pages?

If you want to create and serve your own home pages from the Maths website, here's a checklist of what you will need:

1. a maths UNIX account and a home directory on the ICNFS server

2. a folder called public_html within your ICNFS home directory

3. the access permissions of both your home directory and your public_html folder - and the files within - must be set correctly

4. in most cases, you should have a default page within your public_html folder that will be served if the URL http://wwwf.ma.ic.ac.uk/~username is visited

your ICNFS account

To begin with you will need a home directory on the ICNFS server since your Maths web home pages will be stored in this home directory (even if you have other home directories on other servers as well as a Windows H: drive) and they will be served by the ICT Linux webfarm. ICNFS is a central server managed by ICT that is intended for use by those who mainly use Linux or UNIX desktop PCs and workstations, as opposed to those who primarily use Windows whose home directories will be stored on a different server (the ICT SAN).

Most Linux/UNIX users and some Windows users will already have an account and home directory on the ICNFS server but if you are not sure, one quick way of finding out is to try logging into a Maths Linux system using ssh and your college computer account username and password.

If you are a Windows user, PuTTY is installed on most college Windows machines or you can download this and install it on your own system. Mac and Linux users can simply open a terminal and use ssh from the command line. Try logging into hessian.ma.ic.ac.uk - if it will not accept your college username and password, the chances are high that your college computer account does not permit you to access the ICNFS service and you should contact the ICT service desk.

your public_html folder

By convention, the folder (or subdirectory) within your home directory where your home pages actually reside is called public_html - this is a convention used by all webservers that serve home page content for local users. If this doesn't exist, you will need to create it.

for Linux users: simply use ssh to connect to a Maths Linux system (for example, hessian) and create the subdirectory using the remote command feature of ssh:

ssh username@hessian.ma.ic.ac.uk mkdir public_html

for Windows users: you could log into a Maths Linux system using PuTTY and create a public_html folder on the command line as described above for Linux users but you'll probably feel more at home using Windows Explorer to create your public_html folder and, indeed, doing everything else related to your web home pages. Fortunately, ICNFS also supports mapping a Windows network drive to your home directory or to a folder within it so that it appears to be just another drive on your desktop PC or laptop:

Log onto your Windows PC or laptop using your college username

double click on My Computer



and then select Tools... Map Network Drive...:

choose the drive letter you would like to map to your web home pages - drive W: might be a good choice

in the box labelled Folder: type the following share name:

\\icnfs-ma.cc.ic.ac.uk\your username\public_html

where your username is your college loginname.

now click on Finish to complete the mapping.

the Map Network Drive dialog box will close and you should now see a network drive called public_html on 'wwwf.ma.ic.ac.uk\your username'(disk:) where disk: is the drive letter you have chosen for your mapping.

Note: if you are outside the college, you will need to connect to the college VPN service first because for security reasons, access to Windows network shares is blocked by the college perimeter firewall.

getting the permissions right

The webserver software (apache) needs to be able to read the HTML pages, images and any scripts you may have in your public_html folder otherwise it will not be able to find them and visitors to your home pages will receive the familiar "404 Page not found" error. By default, your ICNFS home directory will have been set up with initial permissions that restrict access to yourself only and deny access to other members of your login group and the world generally, but this will also deny access to the webserver too. So you will need to make some changes to these permissions in such a way as to allow webserver access but not allow others to access your data, which may be very personal.

Your default home directory permissions pattern will look like this:

drwx------

whereas the correct permissions, when you want to allow access to your web pages, should look like this:

drwx--x--x

The extra 'x' characters in the correct pattern allow members of your login group and the world to descend into your home directory and read a known, named and requested filename or path/filename - this is what the webserver will do when asked to access the file public_html/index.html for example; as this is a known file requested by name, access will be possible. But setting these permissions will not allow all and sundry to go into your home directory and/or public_html folder and browse around!

Checking and if necessary correcting the permissions is best done from a Linux or UNIX system (it can be done from Windows but frankly it is quicker and easier to simply log into a Linux system and check/change it there with one or two commands):

1. log into a Maths Linux system (eg, hessian) using either ssh (for UNIX/Linux users) or PuTTY (for Windows users)

2. Now type the following command at the prompt

   ls -ld $HOME

3. Supposing your username is jbloggs, then you should see:

   jbloggs@hessian:~ $ ls -ld $HOME
   drwx--x--x  70 jbloggs ammp 8192 Mar 25 12:12 /home/ma/j/jbloggs

4. If your home directory permission pattern is drwx------ and assuming you are still logged into the Linux system, you will need to correct this by typing:

   jbloggs@hessian:~ $ chmod 711 $HOME

5. and double check that the permissions are now correct:

   jbloggs@hessian:~ $ ls -ld $HOME
   drwx--x--x  70 jbloggs ammp 8192 Mar 25 12:12 /home/ma/j/jbloggs

6. Similarly the permissions of your public_html folder should at least be the same as your home directory at drwx--x--x; if not you can correct this with:

   jbloggs@hessian:~ $ chmod 711 $HOME/public_html

7. and double check that the permissions are now correct:

   jbloggs@hessian:~ $ ls -ld public_html
   drwx--x--x  70 jbloggs ammp 8192 Mar 25 12:12 public_html/

8. Finally, do make sure that the permissions of the web content files - that is the pages, images, scripts, etc that you upload into your public_html folder - also allows the webserver read-only access to them. If you like creating your HTML pages interactively by editing them 'in situ' via a ssh session into a Maths Linux system, the editor will by default save your pages with the correct permissions as in this example:

   jbloggs@hessian:~ $ ls -l public_html
   -rw-r--r-- 1 jbloggs ammp    26402 Sep  4 11:45 index.html

   If you upload content into your public_html from your own computer using scp, sftp or by mapping a network drive in Windows to your public_html folder, the permissions of your uploaded content will usually match those of your files on your own computer allowing read-only access to all, including the webserver. But if you have set unusual permissions for your files on your own system, or if you are using a Windows, a Mac or a third-party Linux sftp or scp program that allows permissions to be changed during the upload so that read access by the webserver is denied, your pages won't display!

   So in addition to making sure your ICNFS home directory and public_html folder permissions are correct, you must make sure that the content's permissions are correct too. Pages, images, scripts and any other files you want to be able to display to visitors to your home pages should be set to:

   rw-r--r--

   and any subdirectories or folders within your public_html folder should have the permissions:

   drwx--x--x

   If your file and/or folder permissions are wrong, you can reset these permissions remotely using most graphical scp or sftp programs for Windows, Mac, Linux, Andoid or iPhone and if you have mapped a Windows network drive to your public_html folder, you can change the permissions from Windows. Alternatively, a quick way of doing this is to log into a Maths Linux system and fix this yourself; if you have a simple set of pages with no subdirectories inside your public_html folder, you can use this remote ssh command:

   ssh username@hessian.ma.ic.ac.uk chmod 644 public_html/*

   to set the correct permissions for your content files. However, if you have subdirectories within your public_html folder, this simple command will make these subfolders inaccessible! In this case the best way to get the permissions right is to first log into a Maths Linux system, say, hessian.ma, and then use the Linux 'find' command to separately find all the files and folders and set their permissions correctly:

   ssh username@hessian.ma.ic.ac.uk
   find ~/public_html -type d -exec chmod 711 {} \;
   find ~/public_html -type f -exec chmod 644 {} \;
   exit

about default pages in your public_html folder

To protect your own security, directory indexes are disabled on the ICT webfarm. This means that:

1. you cannot display a listing of the files or folders within the public_html folder (or any other folder within it or below it) by using a URL that ends with either the user's username or the name of a folder below the public_html folder

2. if one of the defined default top level pages (index.html, index.htm, default.htm or index.php) is not present in the public_html folder, then a URL such as http://wwwf.ma.ic.ac.uk/~username will return an error message like this:
   
   
   
   
3. if one of the default top level pages is not present in any folder, then a URL such as http://wwwf.ma.ic.ac.uk/~username/empty-folder will return an error message like this:
   
   
   
   
4. Do note that a folder that lacks a default index page can still serve a page or file explicitly referred to by the URL, as in the example here:
   
   
   
   

Getting your home page content onto the webserver