Hi Alain, Thanks for replying to my question. > > My understandin is: > You are load balancing your outgoing traffic.... Yes, load balancing outgoing traffic > > > > route add $smtpserver1 netmask 255.255.255.255 gw $publicip1 > > route add $publicip1 gw $gw1 > > You are trying to force the GW for smtpserver1, but .... > Yes, we are trying to the force the gateway for smtpserver1 and smtpserver2 . As both the smtpservers will go through specified ISPs. > > Some more iptables rules which ban sending mails from different > > vlans/lans directly to public ips (both 1 and 2) > > $IPTABLES -A INPUT -p tcp -s $lan1 -d $publicip1 --dport $SMTP -j DROP \ > > > > > > $IPTABLES -A INPUT -p tcp -s $lan2 -d $publicip1 --dport $SMTP -j DROP \ > > > > > > $IPTABLES -A INPUT -p tcp -s $lan3 -d $publicip1 --dport $SMTP -j DROP \ > > > > > > Same rules we have for publicip2. > > > > But still we are not able to send emails from the $smtpserver running > > in the local lan to outside. Our requirement is like this smtpserver1 > > which is running postfix should only send/receive emails through > > publicip1 and smtpserver2 which is also running postfix should > > sends/receive mails through publicip2. > > > > We are able to receive emails both the public ips on the respective > > smtp servers but when we are sending emails to outside world it is > > sometimes going through both the public ips from a single smtp server. > > ... it doesn't work. > > I had a similar problem. > I have create rules in the mangle INPUT table to 'mark' packets , for example: > > 0 for packet that must be load balanced > 1 for packet that must go through first ISP > 2 .... for the second ISP > > Then in my routing rules, I use the mark to use one or another routing table. > Can you mail me an example that will be very helpful for me. Thanks & Regards Ankush