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Date:      Tue, 21 Jan 2003 17:03:09 -0600
From:      Doug Poland <doug@polands.org>
To:        Kirk Strauser <kirk@strauser.com>
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: IPFW, blocking IM servers
Message-ID:  <20030121230308.GA89143@babylon.polands.org>
In-Reply-To: <87hec2jggs.fsf@pooh.honeypot.net>
References:  <34651.63.104.35.130.1043185192.squirrel@email.polands.org> <87hec2jggs.fsf@pooh.honeypot.net>

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On Tue, Jan 21, 2003 at 04:17:07PM -0600, Kirk Strauser wrote:
> 
> At 2003-01-21T21:39:52Z, "Doug Poland" <doug@polands.org> writes:
> 
> > Sorry for this slightly off-topic post...  Is there a comprehensive list
> > of IM servers (names, IPs) available?  I'd like to block IM servers from
> > certain users on my network.
> 
> No, nor will there be one.  Anyone with a server can set up Jabber on any
> port they want.
> 
I'm concerned about the big 3, AOL, MSN, and Yahoo.  They must have a
limited IP range they use.

> > From what I've gathered on google, the only effective stragegy is to use
> > firewall (in my case, IPFW) rules to block IP's, names.
> 
> OK, first, this is really more of an administrative issue than a technical
> one.  Tell your employees that if they IM for non-work issues (and that IM
> is logged, whether it is or not), then they are fired.  Get your boss to
> back you.  Then, it's not *your* problem if people are wasting their time at
> work.
> 
This is my boss's idea!  Also there are also a number of volunteers who
cannot be fired.

> Second, the only reasonable way to do this is to block *everything* except
> traffic you want to allow.  No client machine needs direct Internet access
> to send email - make them use a smarthost.  Force all machines to surf the
> web via a Squid proxy, and only let that machine connect out on port 80.
> 
I'm doing that now, however, I know the Yahoo client will use any open
port it can find and tunnel through that.

> Either way is going to piss off a lot of people, so decide in advance which
> one you can live with.  :)
> 
Actually, this is to head of the problem before it starts.  Thanks for
you input and point of view Kirk.

-- 
Regards,
Doug

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