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From: "Rob Sterenborg" <rob@sterenborg.info>
To: netfilter@lists.netfilter.org
Subject: RE: How to block sending mail from local network.
Date: Sat, 7 Feb 2004 21:17:32 +0100	[thread overview]
Message-ID: <20040207201732.93A41382@sterenborg.info> (raw)
In-Reply-To: <4024C335.7080705@ergolight-sw.com>

> I want to block smtp operations from the local network so the 
> viruses/worms will be blocked.
> 
> I tried a command:
> $IPTABLES -A OUTPUT -p TCP -i $LAN_IFACE -s $LAN_IP_RANGE 
> --dport smtp 
> -j DROP
> but it did nothing.

No, the INPUT and OUTPUT chains are for filtering the local machine : de
firewall itself.
If you want to block clients, you should use the FORWARD chain.

You could use a rule like this one :
$IPTABLES -A FORWARD -i $LAN_IFACE -s $LAN_IP_RANGE -p tcp --dport 25 -j
DROP
or
$IPTABLES -A FORWARD -i $LAN_IFACE -s $LAN_IP_RANGE -p tcp --dport 25 -j
REJECT --reject-with tcp-reset

I suppose you're running your own mailserver ? Otherwise none of your
clients are able to send email.


Gr,
Rob



  parent reply	other threads:[~2004-02-07 20:17 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-02-07 10:51 How to block sending mail from local network David Harel
2004-02-07 20:15 ` Sven Schuster
2004-02-08  9:39   ` David Harel
2004-02-07 20:17 ` Rob Sterenborg [this message]
2004-02-08 15:31 ` Tarek W.
2004-02-08 21:42 ` Alex Satrapa
2004-02-08 22:40 ` Mark Weaver

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