How can I know firewall rules in linux?

Hi,

can explain me the meaning this sentences..?

# iptables -t filter --list

Chain INPUT (policy ACCEPT)

target     prot opt source               destination      

Chain FORWARD (policy ACCEPT)

target     prot opt source               destination      

Chain OUTPUT (policy ACCEPT)

target     prot opt source               destination

and explain the meaning each word:

NAT

IP

Object Name (If any)

Objects (Origin Destination)

NAT Output (if any)

Name Type

Port

Protocol

VPN (including the tunnel)

thanks!