Are there any simpler commands to these? (e.g.: a oneliner? can one command reset iptables/netfilter settings to this?)
IPTABLES="$(which iptables)"
# RESET DEFAULT POLICIES
$IPTABLES -P INPUT ACCEPT
$IPTABLES -P FORWARD ACCEPT
$IPTABLES -P OUTPUT ACCEPT
$IPTABLES -t nat -P PREROUTING ACCEPT
$IPTABLES -t nat -P POSTROUTING ACCEPT
$IPTABLES -t nat -P OUTPUT ACCEPT
$IPTABLES -t mangle -P PREROUTING ACCEPT
$IPTABLES -t mangle -P OUTPUT ACCEPT
# FLUSH ALL RULES, ERASE NON-DEFAULT CHAINS
$IPTABLES -F
$IPTABLES -X
$IPTABLES -t nat -F
$IPTABLES -t nat -X
$IPTABLES -t mangle -F
$IPTABLES -t mangle -X