prerouting and route

["Oğuz Yarımtepe" <comp.ogz@gmail.com>]

Hi,

I gave some points that i couldnt visualize. 
First question is related with the route command. Lets say i defined a local 
route as,

route add 10.2.0.0 netmask 255.255.255.0 gw 10.2.0.1 dev eth1

and while i am configuring iptables i wrote some rules:

# delete all existing rules
iptables -F
iptables -t nat -F
iptables -t mangle -F
iptables -X

# set default policies
iptables -P INPUT DROP
iptables -P FORWARD DROP

iptables -t nat -A PREROUTING -i eth0 -p ALL -d 10.2.0.0/24 -j DNAT --to 
10.2.0.1

At this point i ask myself whether i need this rule, because i had already 
defined a route while configuring interfaces. So is there a relation between 
route definitions and prerouting, is it unnecessary to define a local route 
and try to the same thing with iptables?

Second, i have a rule as,

iptables -t nat -A PREROUTING -i eth1 -p ALL  -j DNAT --to 192.168.1.4

192.168.1.4 is the ip of eth0 which is plugged to a gateway with the ip 
192.168.1.3. If i send a package from eth1 to lets say 192.168.1.10, its 
destination address is replaced with 192.168.1.4. After this point, will it 
continue to 192.168.1.3? If yes how?

Thanx.
 
-- 
Oğuz Yarımtepe
http://www.yarimtepe.com/en