# iptables filter表
- iptables -F #清空所有規則
- service iptables save #保存規則
- iptables -t nat #-t指定表
- iptables -Z #將計數器清零
- iptables -A INPUT -s 192.168.188.1 -p tcp --sport 1234 -d 192.168.188.128 --dport 80 -j DROP
- iptables -I/-A/-D INPUT -s 1.1.1.1 -j DROP
- iptables -I INPUT -s 192.168.1.0/24 -i eth0 -j ACCEPT
- iptables -nvL --line-numbers
- iptables -D INPUT 1
- iptables -P INPUT DROP
```
[root@localhost ~]# iptables -nvL
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
193 12868 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
6 552 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
10 2365 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT 112 packets, 12324 bytes)
pkts bytes target prot opt in out source destination
```
iptables規則記錄在/etc/sysconfig/iptables的配置文件中
```
[root@localhost ~]# cat /etc/sysconfig/iptables
# sample configuration for iptables service
# you can edit this manually or use system-config-firewall
# please do not ask us to add additional ports/services to this default configuration
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT[root@localhost ~]# iptables -F
```
```
[root@localhost ~]# iptables -nvL
Chain INPUT (policy ACCEPT 6 packets, 428 bytes)
pkts bytes target prot opt in out source destination
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
Chain OUTPUT (policy ACCEPT 4 packets, 448 bytes)
pkts bytes target prot opt in out source destination
[root@localhost ~]# cat /etc/sysconfig/iptables
# sample configuration for iptables service
# you can edit this manually or use system-config-firewall
# please do not ask us to add additional ports/services to this default configuration
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A INPUT -p icmp -j ACCEPT
-A INPUT -i lo -j ACCEPT
-A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT
-A INPUT -j REJECT --reject-with icmp-host-prohibited
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT
```
重啟服務，iptables規則重置
```
[root@localhost ~]# service iptables restart
Redirecting to /bin/systemctl restart iptables.service
[root@localhost ~]# iptables -nvL
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
8 576 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT 5 packets, 716 bytes)
pkts bytes target prot opt in out source destination
[root@localhost ~]# service iptables save
```
```
[root@localhost ~]# iptables -t filter -nvL
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
68 4536 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
1 229 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT 38 packets, 5024 bytes)
pkts bytes target prot opt in out source destination
[root@localhost ~]# iptables -t nat -nvL
Chain PREROUTING (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
Chain POSTROUTING (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
```
iptables -Z #將計數器清零pkts和bytes
```
[root@localhost ~]# iptables -Z ; iptables -nvL
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
```
[root[@localhost](https://my.oschina.net/u/570656) ~]# iptables -A INPUT -s 192.168.188.1 -p tcp --sport 1234 -d 192.168.188.128 --dport 80 -j DROP/REJECT
iptables -A #插入到后面
```
[root@localhost ~]# iptables -A INPUT -s 192.168.188.1 -p tcp --sport 1234 -d 192.168.188.128 --dport 80 -j DROP
[root@localhost ~]# iptables -nvL
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
354 23684 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
13 1196 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
383 47064 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
0 0 DROP tcp -- * * 192.168.188.1 192.168.188.128 tcp spt:1234 dpt:80
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT 23 packets, 2212 bytes)
pkts bytes target prot opt in out source destination
```
> 0 0 DROP tcp -- * * 192.168.188.1 192.168.188.128 tcp spt:1234 dpt:80
iptables -I #插入到前面
```
[root@localhost ~]# iptables -I INPUT -p tcp --dport 80 -j DROP
[root@localhost ~]# iptables -nvL
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 DROP tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80
513 35132 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
13 1196 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
384 47308 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
0 0 DROP tcp -- * * 192.168.188.1 192.168.188.128 tcp spt:1234 dpt:80
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT 7 packets, 1156 bytes)
pkts bytes target prot opt in out source destination
```
iptables -D #刪除
```
[root@localhost ~]# iptables -D INPUT -p tcp --dport 80 -j DROP
[root@localhost ~]# iptables -nvL
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
605 42492 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
17 1564 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
672 75245 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
0 0 DROP tcp -- * * 192.168.188.1 192.168.188.128 tcp spt:1234 dpt:80
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT 19 packets, 1972 bytes)
pkts bytes target prot opt in out source destination
[root@localhost ~]# iptables -D INPUT -s 192.168.188.1 -p tcp --sport 1234 -d 192.168.188.128 --dport 80 -j DROP
[root@localhost ~]# iptables -nvL
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
744 55092 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
18 1656 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
673 75489 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT 17 packets, 1628 bytes)
pkts bytes target prot opt in out source destination
```
> 刪除iptables的規則，但是重新書寫一條規則或許太麻煩或者忘記規則的寫法時
```
[root@localhost ~]# iptables -A INPUT -s 192.168.188.1 -p tcp --sport 1234 -d 192.168.188.128 --dport 80 -j DROP
[root@localhost ~]# iptables -I INPUT -p tcp --dport 80 -j DROP
[root@localhost ~]# iptables -nvL
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 DROP tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80
912 70948 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
18 1656 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
674 75718 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
0 0 DROP tcp -- * * 192.168.188.1 192.168.188.128 tcp spt:1234 dpt:80
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT 7 packets, 1364 bytes)
pkts bytes target prot opt in out source destination
```
iptables -nvL --line-number
```
[root@localhost ~]# iptables -nvL --line-number
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
num pkts bytes target prot opt in out source destination
1 0 0 DROP tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80
2 1010 77416 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
3 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0
4 0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
5 18 1656 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
6 674 75718 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
7 0 0 DROP tcp -- * * 192.168.188.1 192.168.188.128 tcp spt:1234 dpt:80
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
num pkts bytes target prot opt in out source destination
1 0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT 59 packets, 7820 bytes)
num pkts bytes target prot opt in out source destination
```
```
[root@localhost ~]# iptables -D INPUT 1
[root@localhost ~]# iptables -D INPUT 7
iptables: Index of deletion too big.
[root@localhost ~]# iptables -D INPUT 6
[root@localhost ~]# iptables -nvL --line-number
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
num pkts bytes target prot opt in out source destination
1 1165 87732 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
2 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0
3 0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
4 19 1748 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
5 674 75718 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
num pkts bytes target prot opt in out source destination
1 0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT 42 packets, 4056 bytes)
num pkts bytes target prot opt in out source destination
```
iptables -P #默認規則
```
[root@localhost ~]# iptables -P OUTPUT DROP
```
> 終端使用DROP規則會使原本數據包在22端口通信，接收不了數據，在返回給客戶端再返回給終端，結果到達不了終端，然后接收不了數據就會導致斷開終端連接，解決辦法到主機上將規則改回ACCEPT
```
[root@localhost ~]# iptables -nvL --line-number
Chain INPUT (policy ACCEPT 0 packets, 0 bytes)
num pkts bytes target prot opt in out source destination
1 1165 87732 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
2 0 0 ACCEPT icmp -- * * 0.0.0.0/0 0.0.0.0/0
3 0 0 ACCEPT all -- lo * 0.0.0.0/0 0.0.0.0/0
4 19 1748 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
5 674 75718 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
num pkts bytes target prot opt in out source destination
1 0 0 REJECT all -- * * 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain OUTPUT (policy DROP 37 packets, 24648 bytes)
num pkts bytes target prot opt in out source destination
[root@localhost ~]# iptables -P OUTPUT ACCEPT
```
> -s #源ip
-p #指定協議
--sport #源端口號
-d #目標ip
--dport #目標端口號
-j #行為
#iptables小案例
```
vi /usr/local/sbin/iptables.sh
#!/bin/bash
ipt="/usr/sbin/iptables"
$ipt -F
$ipt -P INPUT DROP
$ipt -P OUTPUT ACCEPT
$ipt -P FORWARD ACCEPT
$ipt -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
$ipt -A INPUT -s 192.168.133.0/24 -p tcp --dport 22 -J ACCEPT
$ipt -A INPUT -p tcp --dprot 80 -j ACCEPT
$ipt -A INPUT -p tcp --dprot 21 -j ACCEPT
icmp示例
iptables -I INPUT -p icmp --icmp-type 8 -j DROP
```
```
[root@localhost ~]# vim /usr/local/sbin/iptables.sh
#!/bin/bash
ipt="/usr/sbin/iptables"
$ipt -F
$ipt -P INPUT DROP
$ipt -P OUTPUT ACCEPT
$ipt -P FORWARD ACCEPT
$ipt -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
$ipt -A INPUT -s 192.168.133.0/24 -p tcp --dport 22 -j ACCEPT
$ipt -A INPUT -p tcp --dport 80 -j ACCEPT
$ipt -A INPUT -p tcp --dport 21 -j ACCEPT
```
> 在tcp協議里ESTABLISHED是保持連接，RELATED狀態
```
[root@localhost ~]# w
22:10:01 up 1 day, 20:48, 2 users, load average: 0.00, 0.01, 0.05
USER TTY LOGIN@ IDLE JCPU PCPU WHAT
root tty1 06:40 15:23m 0.42s 0.42s -bash
root pts/0 21:50 1.00s 0.45s 0.00s w
[root@localhost ~]# sh /usr/local/sbin/iptables.sh
[root@localhost ~]# iptables -nvL
Chain INPUT (policy DROP 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
28 1848 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 ACCEPT tcp -- * * 192.168.133.0/24 0.0.0.0/0 tcp dpt:22
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:21
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
Chain OUTPUT (policy ACCEPT 15 packets, 1428 bytes)
pkts bytes target prot opt in out source destination
[root@localhost ~]# iptables -nvL
Chain INPUT (policy DROP 1 packets, 229 bytes)
pkts bytes target prot opt in out source destination
41 2712 ACCEPT all -- * * 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
0 0 ACCEPT tcp -- * * 192.168.133.0/24 0.0.0.0/0 tcp dpt:22
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:80
0 0 ACCEPT tcp -- * * 0.0.0.0/0 0.0.0.0/0 tcp dpt:21
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
Chain OUTPUT (policy ACCEPT 27 packets, 3628 bytes)
pkts bytes target prot opt in out source destination
[root@localhost ~]# service iptables restart #此命令為重啟iptables服務
Redirecting to /bin/systemctl restart iptables.service
```
> 可以看出pkts bytes的值正在增長
icmp案例
Windows
```
C:UsersAdministrator>ping 192.168.9.134
正在 Ping 192.168.9.134 具有 32 字節的數據:
來自 192.168.9.134 的回復: 字節=32 時間<1ms TTL=64
來自 192.168.9.134 的回復: 字節=32 時間<1ms TTL=64
來自 192.168.9.134 的回復: 字節=32 時間<1ms TTL=64
來自 192.168.9.134 的回復: 字節=32 時間<1ms TTL=64
192.168.9.134 的 Ping 統計信息:
數據包: 已發送 = 4，已接收 = 4，丟失 = 0 (0% 丟失)，
往返行程的估計時間(以毫秒為單位):
最短 = 0ms，最長 = 0ms，平均 = 0ms
```
Linux
```
[root@localhost ~]# iptables -I INPUT -p icmp --icmp-type 8 -j DROP
```
> 使icmp被禁止了，--icmp-type 8指icmp8種類型
Windows
```
C:UsersAdministrator>ping 192.168.9.134
正在 Ping 192.168.9.134 具有 32 字節的數據:
請求超時。
請求超時。
請求超時。
請求超時。
192.168.9.134 的
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