重置iptables

# reset the default policies in the filter table.
iptables -P INPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -P OUTPUT ACCEPT
# reset the default policies in the nat table.
iptables -t nat -P PREROUTING ACCEPT
iptables -t nat -P POSTROUTING ACCEPT
iptables -t nat -P OUTPUT ACCEPT
# reset the default policies in the mangle table.
iptables -t mangle -P PREROUTING ACCEPT
iptables -t mangle -P OUTPUT ACCEPT
# flush all the rules in the filter and nat tables.
iptables -F
iptables -t nat -F
iptables -t mangle -F
# erase all chains that's not default in filter and nat table.
iptables -X
iptables -t nat -X
iptables -t mangle -X