A replacement for rp_filter with iptables (config help needed)

[Simon <dev@networker.co.nz>]

Hi There,

We are debian sarge with two ethernet cards.. To get eth1 (on a seperate 
subnet) working correctly, ive had to change 
/proc/sys/net/ipv4/conf/eth1/rp_filter to 0. Now i need a simple 
solution to protect against spoofing attacks on this interface... I have 
an example setup, but i want to make sure i have it correct.. can 
someone confirm for me?...

Note, this was a small script to block the mysql port on the server, but 
then enable for certain time/ip dynamically by adding/removing chains.

iptables -F
iptables -A INPUT -i lo -j ACCEPT
iptables -N MYSQL
iptables -N SPOOF
iptables -A INPUT -p tcp --dport 3306 -j MYSQL
iptables -A SPOOF -i eth1 -j SPOOF
iptables -A INPUT -p tcp --dport 3306 -j REJECT --reject-with tcp-reset

Is this correct - or have i got it ALL wrong.

Thanks

Simon