RE: how to block web messenger services

["Petter Bruland" <pbruland () fcglv com>]

Last place I worked, I used Squid and it worked great. And I was not
allowed to block ANY sites, but they didn't say anything about speed. So
I throttled down the speed to sites such as MySpace, Gmail, FaceBook
etc, down 10 Kbps, and then we saw an decrease in surfing to those
sites.

Now where I work, we use Web Sense, which is really nice and we can
block most of the known web based chat sites etc, as well as we can
setup time quota for users. So most of our users can only chat or surf
(where we allow them) for about 30 minutes between 12:00 and 1:00 (lunch
time).
This might not be the best solution, but it works for us at this point.

Although the most important thing is to have a "up to date" policy
manual, which is written in such a way that the end user understands it.
:-)


Squid - http://www.squid-cache.org/
Web Sense - http://www.websense.com/global/en/

-Petter

-----Original Message-----
From: listbounce () securityfocus com [mailto:listbounce () securityfocus com]
On Behalf Of krymson () gmail com
Sent: Monday, March 26, 2007 7:10 AM
To: security-basics () securityfocus com
Subject: Re: how to block web messenger services

First of all, make sure you have a policy about IM systems.

Second, be aware that with all the ajax/web 2.0 sites, having a
web-based IM service is becoming popular and widespread. Are you ready
to keep up with a new site every week that springs up?

Third, you can try to keep up by blocking those sites by IP or DNS at
your firewall or another blocking device. I'd not prefer this method as
it does not scale at all.

Fourth, you will need a web proxy or a web content filtering device
(either that proxies all traffic or sees all HTTP traffic and sends TCP
resets to anything unwanted). This is the best bet, but point 2 still
applies. 

<- snip ->
Hi all ,
i am a security admin,yahoo messenger and other chat services are
blocked on our network, but we can access them thru web(ebuddy) , i
wanted to know how can we make sure that these chat services (yahoo
messenger, icq, msn messeger ) cannot be accessed through web as well ,
i mean how to block them.
thanks