Got three HTTP/S proxies listening on ports 1001, 1002 and 1003 on 192.168.0.1. On another system on the same network, firefox is set to use the 192.168.0.1:1001 proxy. Is it possible with iptables or otherwise in the server system, to use all proxies in a round robin fashion?

Inspired from this nice article but we want to round robin connections, not to send packets in a round robin fashion. As in, the first connection gets the HTML code of a web page using the 1001 proxy, the next connection gets an image using the 1002 proxy and so on.

Or does the article round robin connections? And therefore the following is what is needed?

iptables -A PREROUTING -t nat -p tcp -d 192.168.0.1 --dport 1001 \
-m statistic --mode nth --every 3 --packet 0 \
-j DNAT --to-destination 192.168.0.1:1001

iptables -A PREROUTING -t nat -p tcp -d 192.168.0.1 --dport 1001 \
-m statistic --mode nth --every 2 --packet 0 \
-j DNAT --to-destination 192.168.0.1:1002

iptables -A PREROUTING -t nat -p tcp -d 192.168.0.1 --dport 1001 \
-j DNAT --to-destination 192.168.0.1:1003

Or is "ip route" the way to do it (after adding virtual nic's eth1, eth2 and eth3 on both systems and respective virtual cables and static IP's), ie doing this on the client:

ip route add default scope global \
nexthop via 192.168.1.1 dev eth1 weight 1 \
nexthop via 192.168.2.1 dev eth2 weight 1 \
nexthop via 192.168.3.1 dev eth3 weight 1

and on the server:

iptables -A PREROUTING -t nat -p tcp -i eth1 --dport 1001 \
-j DNAT --to-destination 192.168.0.1:1001

iptables -A PREROUTING -t nat -p tcp -i eth2 --dport 1001 \
-j DNAT --to-destination 192.168.0.1:1002

iptables -A PREROUTING -t nat -p tcp -i eth3 --dport 1001 \
-j DNAT --to-destination 192.168.0.1:1003

Can this be simplified somehow?