1. Remove the following line, if it exists, in /etc/sysconfig/iptables-config
IPTABLES_MODULES="ip_conntrack_netbios_ns"
2. Stop iptables
iptables -F
3. Remove the related modules
modprobe -r xt_NOTRACK nf_conntrack_netbios_ns nf_conntrack_ipv4 xt_state
modprobe -r iptable_nat ipt_MASQUERADE nf_nat nf_defrag_ipv4
modprobe -r nf_conntrack
