Static NAT Mappings

["John Black" <black@xxxxxxxxx>]

I'm trying to setup static NAT mappings.

this is what i did, but it doesn't work:
public address 1.2.3.4/24
ifconfig eth0:0 1.2.3.4 netmask 255.255.255.0

then in my firwall script:
iptables -t nat -A POSTROUTING -s 192.168.0.4 \
 -o eth0 -j SNAT --to 1.2.3.4

i tried this also:
iptables -t nat -A POSTROUTING -s 192.168.0.4/24
  -o eth0 -j SNAT --to 1.2.3.4

i have read the howto on the netfilter web site. 
but i'm still lost.


thanks
john