其实问题出在/etc/sysconfig/iptables-config,打开它:
vi /etc/sysconfig/iptables-config
# Load additional iptables modules (nat helpers)
# Default: -none-
# Space separated list of nat helpers (e.g. 'ip_nat_ftp ip_nat_irc'), which
# are loaded after the firewall rules are applied. Options for the helpers are
# stored in /etc/modprobe.conf.
IPTABLES_MODULES="" //就是这一行,补全就行。
改
IPTABLES_MODULES="ip_conntrack_netbios_ns ip_conntrack_ftp ip_nat_ftp"