Assuming eth0 is the NIC that your internal clients connect to and that it has IP 192.168.1.1: REDIRECT or NAT any traffic coming into eth0 on port 25 to your firewall: iptables -t nat -A PREROUTING -i eth0 p tcp --dport 25 -j DNAT --to 192.168.1.1:25 ALLOW the connections to your firewall: iptables -t filter -A INPUT -i eth0 -p tcp -d 192.168.1.1 --dport 25 -j ACCEPT This should take care of redirecting port 25 traffic to your firewall. Configuration of your smtp server is outside scope of this mailing list. -Sietse ________________________________ From: netfilter-bounces@xxxxxxxxxxxxxxxxxxx on behalf of Don Gould Sent: Sat 05-Aug-06 11:52 To: netfilter@xxxxxxxxxxxxxxxxxxx Subject: SMTP Redirect - 'This is it'... Hi, Is there a way to fool the mail client into thinking that a call to 'smtp.someonelse.whateva.com' is my local server? I have people visiting my network with laptops. Getting mail off their POP server is no problem. Sending mail is a problem as my up stream provider blocks links.... So I want my server on my network to intercept the call on port 25 for a remote smtp server and then just lie to the laptop. This gives me the advantage of not having to reconfigure the users machine when they leave my network. Cheers Don -- Don Gould www.thinkdesignprint.co.nz - www.tcn.bowenvale.co.nz - www.bowenvale.co.nz - www.hearingbooks.co.nz - SkypeMe: ThinkDesignPrint
