iptables is software for adjusting/setting the kernels packet handling options, it doesnt run as a daemon
iptables -L will list the current ruleset
iptables -F will flush the current ruleset
normally the ruleset defaults to everything open or closed, depends on distro
echo 0 > /proc/sys/net/ipv4/ip_forward should disable packet forwarding I think,not sure if debian uses that exact location for the variable