FORWARD allow ftp?

["michael" <michael@etalon.net>]

Hello,

I wanted to allow my clients behind my firewall to use ftp.
I've added the rules to my iptables script.

-A FORWARD -p tcp -m tcp --dport 21 -j ACCEPT
-A FORWARD -p tcp -m tcp --dport 20 -j ACCEPT
-A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT

Just wanted to get your opinion if this is the correct 
way to do it? The 3rd rule above (--state....) is the one rule
I'm mostly unsure about. Is this the proper way to allow ftp access?
What rules do you guys use for ftp?

Thanks
Mike