在iptables服务开启的状态测试不会出现unknown key的错误，我们尝试关闭

iptables .

[root@DT2MISPDB ~]# service iptables stop

Flushing firewall rules: [ OK ]

Setting chains to policy ACCEPT: nat filter [ OK ]

Unloading iptables modules: [ OK ]

[root@DT2MISPDB ~]#

[root@DT2MISPDB etc]# service iptables status

Firewall is stopped.

[root@DT2MISPDB etc]# sysctl -p

net.ipv4.ip_forward = 0

net.ipv4.conf.default.rp_filter = 1

net.ipv4.conf.default.accept_source_route = 0

kernel.sysrq = 0

kernel.core_uses_pid = 1

net.ipv4.tcp_syncookies = 1

kernel.msgmnb = 65536

kernel.msgmax = 65536

kernel.shmall = 2097152

kernel.shmmax = 3221225472

kernel.shmmni = 4096

kernel.sem = 250 32000 100 128

fs.file-max = 6815744

net.ipv4.ip_local_port_range = 9000 65500

net.core.rmem_default = 262144

net.core.rmem_max = 4194304

net.core.wmem_default = 262144

net.core.wmem_max = 1048576

fs.aio-max-nr = 1048576

error: "net.ipv4.ip_conntrack_max" is an unknown key

[root@DT2MISPDB etc]#

发现错误出现：

error: "net.ipv4.ip_conntrack_max" is an unknown key

使用modprobe载入ip_conntrack模块，lsmod查看模块已载入。

[root@DT2MISPDB etc]# modprobe ip_conntrack

[root@DT2MISPDB etc]# lsmod

Module Size Used by

ip_conntrack 53281 0

再次关闭iptables服务，查看

[root@DT2MISPDB etc]# service iptables stop

Flushing firewall rules: [ OK ]

Setting chains to policy ACCEPT: filter [ OK ]

Unloading iptables modules: [ OK ]

[root@DT2MISPDB etc]#

[root@DT2MISPDB etc]# lsmod

结果没有发现ip_conntrack 模组。

问题 ：

1. Linux下加载及卸载模块是什么意思 ？ 这里的模块都是指核心模块 ？

2. 加载 ip_conntrack 模块和 iptables 服务以及 通过service iptables start 有什么关系 ？