iptables newbie question

[jon182]

Hey guys i am very new to iptables and was just wondering what the following commands do and what type of attacks they would prevent.

Am I correct in assuming the first command allows traffic from port 80?

I am a bit confused so any help would be great thanks.

iptables -I FORWARD 1 -p tcp -dport 80 -j ACCEPT

iptables -I FORWARD 2 -p tcp -sport 80 -j ACCEPT

[framp]

Am I correct in assuming the first command allows traffic from port 80?

There are different queues used by iptables: The FORWARD queue which forwards requests to other systems (That's your example) and INPUT/OUTPUT queues (local queues of the system the iptables rules is acive).

If the destination port 80 is local: NO
If the destination port 80 is on a system connected on a different nic: YES

[jon182]

Thanks for the reply after the forward command why is there a number in this case 1 and 2?

thanks again

[framp]

Frankly - I missed this. I used 'man iptables' and found out it's a rule number. I never needed this rulenumber for my FW rules.