iptables 学习总结--扩展模块udp和icmp,state(五)

朱雀 2022-05-23 05:12 128阅读 0赞

## udp扩展 ##

匹配源端口`--sport`  
匹配目标端口`--dport`

iptables -t filter -A INPUT -p dup -m udp --dport 137 -j REJECT
    iptables -t filter -A INPUT -p dup -m udp --dport 138 -j REJECT

端口范围

iptables -t filter -A INPUT -p dup -m udp --dport 136:137 -j REJECT

## icmp扩展 ##

ping 走的是icmp协议

iptables -t filter -I INPUT ip icmp -m icmp --icmp-type 8/0 -j REJEST
    
    iptables -t filter -I INPUT ip icmp -m icmp --icmp-type 8 -j REJEST
    
    iptables -t filter -I INPUT ip icmp -m icmp --icmp-type "echo-request" -j REJEST

## state扩展 ##

状态–连接追踪：

NEW--新建连接第一个报文
     ESTABLISHED 已建立连接
     RELATED 命令连接 如FTP连接
    INVALID 没有办法呗识别的连接
    UNTRACKED 报文违背跟踪

禁止新的连接的建立

iptables -t filter -I INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT

--------------------

## 自定义链 ##

除了iptables 提供的INPUT PREROUTING FORWARD POSTROUTING OUTPUT链之外我们还可以自定义链

[root@localhost ~]# iptables -t filter -N INWEB
    [root@localhost ~]# iptables -t filter -nvxL | grep INWEB
    Chain INWEB (0 references)

[root@localhost ~]# iptables -t filter -nvxL INWEB
    Chain INWEB (0 references)
        pkts      bytes target     prot opt in     out     source               destination

添加规则

root@localhost ~]# iptables -t filter -I INWEB -s 192.168.2.2 -d 192.168.1.3 -j ACCEPT
    [root@localhost ~]# iptables -t filter -nvxL INWEB
    Chain INWEB (0 references)
        pkts      bytes target     prot opt in     out     source               destination
           0        0 ACCEPT     all  --  *      *       192.168.2.2          192.168.1.3

引用

[root@localhost ~]# iptables -t filter -A INPUT -s 192.168.2.2 -d 92.168.1.3 -j INWEB
    [root@localhost ~]# iptables -t filter -nvxL INWEB
    Chain INWEB (1 references)
        pkts      bytes target     prot opt in     out     source               destination
           0        0 ACCEPT     all  --  *      *       192.168.2.2          192.168.1.3

删除自定义链

[root@localhost ~]# iptables -t filter -X INWEB
    iptables: Too many links.
    [root@localhost ~]# iptables -t filter -A INPUT -s 192.168.2.2 -d 92.168.1.3 -j INWEB^C
    [root@localhost ~]# iptables -t filter -nvxL INPUT
    Chain INPUT (policy ACCEPT 58 packets, 4048 bytes)
        pkts      bytes target     prot opt in     out     source               destination
           0        0 INWEB      all  --  *      *       192.168.2.2          92.168.1.3
    [root@localhost ~]# iptables -t filter -D INPUT 1
    [root@localhost ~]# iptables -t filter -X INWEB
    iptables: Directory not empty.
    [root@localhost ~]# iptables -t filter -D INWEB 1
    [root@localhost ~]# iptables -t filter -X INWEB

参考：  
[扩展模块udp和icmp][udp_icmp]

[udp_icmp]: http://www.zsythink.net/archives/1588