Send all incoming traffic on an interface to a listening port (iptables)

From ben.goodacre.name/tech

Send all incoming TCP traffic on interface eth1 to port 3128 on any interface:

sudo iptables -A PREROUTING -i eth1 -p tcp -j REDIRECT --to-ports 3128

iptables output should look like:

# iptables -t nat -nvL PREROUTING
Chain PREROUTING (policy ACCEPT 516K packets, 51M bytes)
 pkts bytes target     prot opt in     out     source               destination   
....      
xxxK  xxxM REDIRECT   tcp  --  eth1   *       0.0.0.0/0            0.0.0.0/0           redir ports 3128