is this make sense: iptables -A PREROUTING -t nat -j SNAT --to 0.0.0.0

[Nguyen Dinh Nam <64vn@cardvn.net>]

Currently, SNAT/MASQ is only allowed in POSTROUTING/nat so at the 
internet gateway, everyone is doing something like this:
iptables -A POSTROUTING -t nat -o $external_interface -j SNAT --to 
$external_ip

But I think that this approach is more interesting
iptables -A PREROUTING -t nat -j SNAT --to 0.0.0.0

The rule clears the source IP address from the packet, later, routing 
code will bind an ip address to the packet based on routing decision. In 
the case where the host has several internet providers, the traditional 
method needs several rules, as well as using CONNMARK to bind each TCP 
connection to only one internet provider. If this new approach is 
possible, it'll simplify the problem tremendously

I've never touched netfilter source code so I don't know if it's 
possible, it may be just a stupid idea.