[CentOS] Problems with 'iptables'

Hello!

Sorry if this question is already asked, but I not finding answer for it... I have server with CentOS 6.4, later it will be router for home network.

When I tried tune iptables I have error: [root@gateway sysconfig]# iptables -t NAT -A POSTROUTING -o eth0 -j MASQUERADE iptables v1.4.7: can't initialize iptables table `NAT': Table does not exist (do you need to insmod?) Perhaps iptables or your kernel needs to be upgraded.

iptables 1.4.7 (latest version), custom kernel 3.8.3. from kernel.org (too latest version)

How to fix this error, it's desirable without rebuild kernel?