[WEB4LIB] Blocking web-based chat

[josh at saratoga.lib.ny.us]

> --what software are you using?

I'm using Squid (http://www.nlanr.net/squid or
http://www.squid-cache.org/) with success on Linux (there is an NT
version - though not as current). I am sure this post has more than
most readers want to know, but I imangine everyone will have similar
problems regardless what software they are using. It took a while to
find the details as well as corresponence with one of the authors
about the syntax of the commands to figure out how to configure it
correctly. I still have a way to go. 

I started with Dan's list at http://www.84.com/blacklist.htm. There
are some problems with that list. I will of course send Dan my
solutions when I get there - but I'm going to outline it here. The
main problems are his list doesn't distinguish between chat, games,
and e-mail. (We block chat and games altogether but simply restrict
e-mail to some machines) This is acknowledged on the web page. The
second problem was how to block only the chat services on sites that
offer a lot more. For example http://123india.com is on his list as it
provides access to chat and e-mail, but it is also a very good soure
of information about India.

I'm including an example extracted from my configuration file for
Squid. Squid supports regular-expressions and has a built in
mechanisms for blocking based on the start or end of a URL. Here is an
example how to block the chat sites at about.com, but nothing else,
using Squid.

The lines below are from my squid.conf file with the comments above
hopefully explaining what I'm doing clearly enough to illustrate the
problem and the solution.

#this line makes 'somemachines' a way to refer to all the machines
#with IP address from 192.168.200.1 to 192.168.200.254 on my
#private network.
acl somemachines src 192.168.200.0/24
# this lets me refer to the domain about.com as with the text 
# string 'about.com'
acl about.com dstdomain about.com  
# this give me a way to refer to web-sites in the about.com domain
# that end with either 'mpchat.htm' or 'parachat.htm' The sites you need to
# access to get into any of their numerous chat rooms at about.com
#  
acl about.com_chat urlpath_regex mpchat.htm parachat.htm  
#finally tell the proxy that PCs referred to as somemachines
# can't access the sites in about.com domain which end with mpchat.htm 
# or parachat.htm                       
http_access deny somemachines about.com about.com_chat   
#

Note that if every chat site in the world was using the same ten
programs with the same names, (e.g. mpchat.htm mpchat.html, chat.pl,
etc) I could just block chat sites. Sadly as far as I can tell there
is too much variety to safely just block sites that contain chat as
the final part of their URL. This example shows how to do one site for
illustrative purposes. It is standard to keep lists in files and use a
command to insert them.

> --is any library successfully using software (or any other method) to
> differentiate chat sites that might be useful from purely recreational
> sites?
> --has any library decided against blocking chat, either because some chat
> sites may be useful to some patrons, or because of 
> reluctance to censor resources?

Our decision was made our of frustration that chat was becoming the
sole use of our Internet PCs. In our ideal we will have Internet
access readily available and the demand for Chat was using up all the
access we provide. We just block chat, games, and limit e-mail. 

I still have mixed feelings about this. I often play freecell when I'm
trying to think though how to do something. Yet, when I look through
my logs I see how much time and bandwidth get swallowed. We have had
machines tied up for hours at http://www.candystand.com a fine site
which exist to sell Life Savers, but offers a game arcade that had
become addictive to many of our patrons.

I managed to get an MS in computer science totally unaware of the
existence of chat. I didn't find out about it until I worked as a
systems administrator at a university. It should be noted that the
most serious chatting is done through three resources ICQ, AIM, and
IRC. Library patrons chatting through web-browsers have second class
citizen status in the chatting world.


-- 
Josh Kuperman                       josh at saratoga.lib.ny.us
Saratoga Springs Public Library     phone (518) 584-7860 x 211
49 Henry St                         fax   (518) 584-7866
Saratoga Springs, NY 12866