How to block Yahoo Messenger through IP Tables

How to block Yahoo Messenger through IP Tables

[Alok Shukla]

Hi ,

Sorry for asking this newbie question first.

I am running a network with a Linux Server as a
gateway. I am using IPtables as to masquerade internal
IPs for Internet usage. I want to block the uses of my
intranet for using yahoo messenger. I needed help for
this. In general i wanted to know how to block a
particular port.

Thanks in Advance

Alok Shukla

__________________________________________________
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Re: How to block Yahoo Messenger through IP Tables

[Krishna]

Hi,

    But why do you want to do that? If you want to block a particular
port then either disable it in inetd or xinetd. Or make rules 
for that destination port to DROP packets.


regards
Krishna

Krishna Shekhar
Network Administrator
Wiplash Wireless

On Sat, 2002-10-05 at 11:59, Alok Shukla wrote:
> Hi ,
> 
> Sorry for asking this newbie question first.
> 
> I am running a network with a Linux Server as a
> gateway. I am using IPtables as to masquerade internal
> IPs for Internet usage. I want to block the uses of my
> intranet for using yahoo messenger. I needed help for
> this. In general i wanted to know how to block a
> particular port.
> 
> Thanks in Advance
> 
> Alok Shukla
> 
> __________________________________________________
> Do you Yahoo!?
> Faith Hill - Exclusive Performances, Videos & More
> http://faith.yahoo.com
> 

Re: How to block Yahoo Messenger through IP Tables

[Nick Drage]

On Sat, Oct 05, 2002 at 05:00:31AM -0400, Krishna wrote:
>     But why do you want to do that? If you want to block a particular
> port then either disable it in inetd or xinetd. Or make rules 
> for that destination port to DROP packets.

As the OP stated, the Linux box is being used as a gateway.  The Yahoo
Messenger servers are out on the Net, so you'll need to block traffic going
through the host, so inetd and xinetd won't help. 

> > Sorry for asking this newbie question first.
> > 
> > I am running a network with a Linux Server as a gateway. I am using
> > IPtables as to masquerade internal IPs for Internet usage. I want to
> > block the uses of my intranet for using yahoo messenger. I needed help
> > for this. In general i wanted to know how to block a particular port.

It's not a newbie question at all, and sounds very familiar.  Have you
Googled for it throughly?  IIRC Yahoo Messenger tries some interesting ways
to get through firewalls - so you might want to filter on destination IP, or
do some kind of content matching fun.  I would expect a lot of people are up
against similar problems so someone will have found a solution already if
there's one to be found.

-- 
FunkyJesus System Administration Team