Linux下iptables 禁止端口和开放端口示例

像昵發表於 2023-7-5 00:00:00

Linux下iptables 禁止端口和开放端口示例

<p>
<strong>1、关闭所有的 INPUT FORWARD OUTPUT 只对某些端口开放。</strong></p>
<p>
下面是命令实现：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_573324">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain">iptables -P INPUT DROP</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">iptables -P FORWARD DROP</code>
</div>
<div class="line number3 index2 alt2">
<code class="bash plain">iptables -P OUTPUT DROP</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
再用命令</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_95403">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain">iptables -L -n</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
查看是否设置好，好看到全部 DROP 了</p>
<p>
这样的设置好了，我们只是临时的，重启服务器还是会恢复原来没有设置的状态</p>
<p>
还要使用 service iptables save 进行保存</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_954759">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain">service iptables save</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
看到信息 firewall rules 防火墙的规则其实就是保存在 /etc/sysconfig/iptables</p>
<p>
可以打开文件查看 vi /etc/sysconfig/iptables</p>
<p>
<strong>2、下面我只打开22端口，看我是如何操作的，就是下面2个语句</strong></p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterplain" id="highlighter_60670">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="plain plain">iptables -A INPUT -p tcp --dport 22 -j ACCEPT</code>
</div>
<div class="line number2 index1 alt1">
<code class="plain plain">iptables -A OUTPUT -p tcp --sport 22 -j ACCEPT</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
再查看下 iptables -L -n 是否添加上去, 看到添加了</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterplain" id="highlighter_44917">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
<div class="line number5 index4 alt2">
5</div>
<div class="line number6 index5 alt1">
6</div>
<div class="line number7 index6 alt2">
7</div>
<div class="line number8 index7 alt1">
8</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="plain plain">Chain INPUT (policy DROP)</code>
</div>
<div class="line number2 index1 alt1">
<code class="plain plain">target   prot opt source        destination</code>
</div>
<div class="line number3 index2 alt2">
<code class="plain plain">ACCEPT   tcp -- 0.0.0.0/0      0.0.0.0/0      tcp dpt:22</code>
</div>
<div class="line number4 index3 alt1">
<code class="plain plain">Chain FORWARD (policy DROP)</code>
</div>
<div class="line number5 index4 alt2">
<code class="plain plain">target   prot opt source        destination</code>
</div>
<div class="line number6 index5 alt1">
<code class="plain plain">Chain OUTPUT (policy DROP)</code>
</div>
<div class="line number7 index6 alt2">
<code class="plain plain">target   prot opt source        destination</code>
</div>
<div class="line number8 index7 alt1">
<code class="plain plain">ACCEPT   tcp -- 0.0.0.0/0      0.0.0.0/0      tcp spt:22</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
现在Linux服务器只打开了22端口，用putty.exe测试一下是否可以链接上去。</p>
<p>
可以链接上去了，说明没有问题。</p>
<p>
最后别忘记了保存对防火墙的设置</p>
<p>
通过命令：service iptables save 进行保存</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_392553">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain">iptables -A INPUT -p tcp --dport 22 -j ACCEPT</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">iptables -A OUTPUT -p tcp --sport 22 -j ACCEPT</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
针对这2条命令进行一些讲解吧</p>
<p>
-A 参数就看成是添加一条 INPUT 的规则<br>
-p 指定是什么协议我们常用的tcp 协议，当然也有udp 例如53端口的DNS</p>
<p>
到时我们要配置DNS用到53端口大家就会发现使用udp协议的</p>
<p>
而 --dport 就是目标端口当数据从外部进入服务器为目标端口</p>
<p>
反之数据从服务器出去则为数据源端口使用 --sport</p>
<p>
-j 就是指定是 ACCEPT 接收或者 DROP 不接收</p>
<p>
<strong>3、禁止某个IP访问</strong></p>
<p>
1台Linux服务器,2台windows xp 操作系统进行访问</p>
<p>
Linux服务器ip: 192.168.1.99</p>
<p>
xp1 ip: 192.168.1.2<br>
xp2 ip: 192.168.1.8</p>
<p>
下面看看2台xp 都可以访问的</p>
<p>
192.168.1.2 这是 xp1 可以访问的，<br>
192.168.1.8 xp2 也是可以正常访问的。</p>
<p>
那么现在我要禁止 192.168.1.2 xp1 访问， xp2 正常访问，</p>
<p>
下面看看演示</p>
<p>
通过命令</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_541273">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain">iptables -A INPUT -p tcp -s 192.168.1.2 -j DROP</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
这里意思就是 -A 就是添加新的规则，怎样的规则呢？由于我们访问网站使用tcp的，</p>
<p>
我们就用 -p tcp , 如果是 udp 就写udp，这里就用tcp了， -s就是来源的意思，</p>
<p>
ip来源于 192.168.1.2 ，-j 怎么做我们拒绝它这里应该是 DROP</p>
<p>
好，看看效果。好添加成功。下面进行验证一下是否生效</p>
<p>
一直出现等待状态最后该页无法显示，这是 192.168.1.2 xp1 的访问被拒绝了。</p>
<p>
再看看另外一台 xp 是否可以访问，是可以正常访问的 192.168.1.8 是可以正常访问的</p>
<p>
<strong>4、如何删除规则</strong></p>
<p>
首先我们要知道这条规则的编号，每条规则都有一个编号</p>
<p>
通过 iptables -L -n --line-number 可以显示规则和相对应的编号</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterplain" id="highlighter_919837">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
<div class="line number5 index4 alt2">
5</div>
<div class="line number6 index5 alt1">
6</div>
<div class="line number7 index6 alt2">
7</div>
<div class="line number8 index7 alt1">
8</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="plain plain">iptables -L -n --line-number</code>
</div>
<div class="line number2 index1 alt1">
<code class="plain plain">num target   prot opt source        destination</code>
</div>
<div class="line number3 index2 alt2">
</div>
<div class="line number4 index3 alt1">
<code class="plain plain">1 DROP    tcp -- 0.0.0.0/0      0.0.0.0/0      tcp dpt:3306</code>
</div>
<div class="line number5 index4 alt2">
</div>
<div class="line number6 index5 alt1">
<code class="plain plain">2 DROP    tcp -- 0.0.0.0/0      0.0.0.0/0      tcp dpt:21</code>
</div>
<div class="line number7 index6 alt2">
</div>
<div class="line number8 index7 alt1">
<code class="plain plain">3 DROP    tcp -- 0.0.0.0/0      0.0.0.0/0      tcp dpt:80 </code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
多了 num 这一列，这样我们就可以看到刚才的规则对应的是编号2</p>
<p>
那么我们就可以进行删除了</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterplain" id="highlighter_34961">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="plain plain">iptables -D INPUT 2</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
删除INPUT链编号为2的规则。</p>
<p>
再 iptables -L -n 查看一下已经被清除了。</p>
<p>
<strong>5、过滤无效的数据包</strong></p>
<p>
假设有人进入了服务器，或者有病毒木马程序，它可以通过22，80端口像服务器外传送数据。</p>
<p>
它的这种方式就和我们正常访问22，80端口区别。它发向外发的数据不是我们通过访问网页请求而回应的数据包。</p>
<p>
下面我们要禁止这些没有通过请求回应的数据包，统统把它们堵住掉。</p>
<p>
iptables 提供了一个参数是检查状态的，下面我们来配置下 22 和 80 端口，防止无效的数据包。</p>
<p>
</p>
<div class="codetitle">
<span><u>复制代码</u></span> 代码如下:</div>
<div class="codebody" id="code80717">
<br>
iptables -A OUTPUT -p tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT</div>
<p>
</p>
<p>
可以看到和我们以前使用的：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterplain" id="highlighter_807987">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="plain plain">iptables -A OUTPUT -p tcp --sport 22 -j ACCEPT</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
多了一个状态判断。</p>
<p>
同样80端口也一样，现在删掉原来的2条规则，</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterplain" id="highlighter_304829">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="plain plain">iptables -L -n --line-number</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
查看规则而且带上编号。我们看到编号就可以</p>
<p>
删除对应的规则了。</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterplain" id="highlighter_778005">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="plain plain">iptables -D OUTPUT 1</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
这里的1表示第一条规则。</p>
<p>
当你删除了前面的规则，编号也会随之改变。</p>
<p>
好，我们删除了前面2个规则，22端口还可以正常使用，说明没问题了</p>
<p>
下面进行保存，别忘记了，不然的话重启就会还原到原来的样子。</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterplain" id="highlighter_685390">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="plain plain">service iptables save</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
进行保存。</p>
<p>
Saving firewall rules to /etc/sysconfig/iptables:          [ OK ]</p>
<p>
其实就是把刚才设置的规则写入到 /etc/sysconfig/iptables 文件中。</p>
<p>
<strong>6、DNS端口53设置</strong></p>
<p>
下面我们来看看如何设置iptables来打开DNS端口，DNS端口对应的是53</p>
<p>
目前只开放22和80端口，我现在看看能不能解析域名。</p>
<p>
hostwww.google.com  </p>
<p>
输入这个命令后，一直等待，说明DNS不通</p>
<p>
出现下面提示：;; connection timed out; no servers could be reached</p>
<p>
ping 一下域名也是不通</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_878549">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain"></code><code class="bash comments">#pingwww.google.com</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash functions">ping</code><code class="bash plain">: unknown hostwww.google.com</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
我这里的原因就是 iptables 限制了53端口。</p>
<p>
有些服务器，特别是Web服务器减慢，DNS其实也有关系的，无法发送包到DNS服务器导致的。</p>
<p>
下面演示下如何使用 iptables 来设置DNS 53这个端口，如果你不知道域名服务端口号，你</p>
<p>
可以用命令 :</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterplain" id="highlighter_331949">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="plain plain">grep domain /etc/services</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_302244">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
<div class="line number5 index4 alt2">
5</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain"> ~ </code><code class="bash comments">#grep domain /etc/services</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">domain     53</code><code class="bash plain">/tcp</code>             <code class="bash comments"># name-domain server</code>
</div>
<div class="line number3 index2 alt2">
<code class="bash plain">domain     53</code><code class="bash plain">/udp</code>
</div>
<div class="line number4 index3 alt1">
<code class="bash plain">domaintime   9909</code><code class="bash plain">/tcp</code>            <code class="bash comments"># domaintime</code>
</div>
<div class="line number5 index4 alt2">
<code class="bash plain">domaintime   9909</code><code class="bash plain">/udp</code>            <code class="bash comments"># domaintime</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
看到了吧，我们一般使用 udp 协议。</p>
<p>
好了，开始设置。。。</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterplain" id="highlighter_964175">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="plain plain">iptables -A OUTPUT -p udp --dport 53 -j ACCEPT</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
这是我们 ping 一个域名，数据就是从本机出去，所以我们先设置 OUTPUT，</p>
<p>
我们按照ping这个流程来设置。</p>
<p>
然后 DNS 服务器收到我们发出去的包，就回应一个回来</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterplain" id="highlighter_918369">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="plain plain">iptables -A INPUT -p udp --sport 53 -j ACCEPT</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
同时还要设置</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterplain" id="highlighter_136591">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="plain plain">iptables -A INPUT -p udp --dport 53 -j ACCEPT</code>
</div>
<div class="line number2 index1 alt1">
<code class="plain plain">iptables -A OUTPUT -p udp --sport 53 -j ACCEPT</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
好了，下面开始测试下，可以用 iptables -L -n 查看设置情况，确定没有问题就可以测试了</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterplain" id="highlighter_562897">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
<div class="line number5 index4 alt2">
5</div>
<div class="line number6 index5 alt1">
6</div>
<div class="line number7 index6 alt2">
7</div>
<div class="line number8 index7 alt1">
8</div>
<div class="line number9 index8 alt2">
9</div>
<div class="line number10 index9 alt1">
10</div>
<div class="line number11 index10 alt2">
11</div>
<div class="line number12 index11 alt1">
12</div>
<div class="line number13 index12 alt2">
13</div>
<div class="line number14 index13 alt1">
14</div>
<div class="line number15 index14 alt2">
15</div>
<div class="line number16 index15 alt1">
16</div>
<div class="line number17 index16 alt2">
17</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="plain plain">[root@localhost ~iptables -L -n</code>
</div>
<div class="line number2 index1 alt1">
<code class="plain plain">Chain INPUT (policy DROP)</code>
</div>
<div class="line number3 index2 alt2">
<code class="plain plain">target   prot opt source        destination</code>
</div>
<div class="line number4 index3 alt1">
<code class="plain plain">ACCEPT   tcp -- 0.0.0.0/0      0.0.0.0/0      tcp dpt:22</code>
</div>
<div class="line number5 index4 alt2">
<code class="plain plain">ACCEPT   tcp -- 0.0.0.0/0      0.0.0.0/0      tcp dpt:80</code>
</div>
<div class="line number6 index5 alt1">
<code class="plain plain">ACCEPT   udp -- 0.0.0.0/0      0.0.0.0/0      udp spt:53</code>
</div>
<div class="line number7 index6 alt2">
<code class="plain plain">ACCEPT   udp -- 0.0.0.0/0      0.0.0.0/0      udp dpt:53</code>
</div>
<div class="line number8 index7 alt1">
</div>
<div class="line number9 index8 alt2">
<code class="plain plain">Chain FORWARD (policy DROP)</code>
</div>
<div class="line number10 index9 alt1">
<code class="plain plain">target   prot opt source        destination</code>
</div>
<div class="line number11 index10 alt2">
</div>
<div class="line number12 index11 alt1">
<code class="plain plain">Chain OUTPUT (policy DROP)</code>
</div>
<div class="line number13 index12 alt2">
<code class="plain plain">target   prot opt source        destination</code>
</div>
<div class="line number14 index13 alt1">
<code class="plain plain">ACCEPT   tcp -- 0.0.0.0/0      0.0.0.0/0      tcp spt:22 state ESTABLISHED</code>
</div>
<div class="line number15 index14 alt2">
<code class="plain plain">ACCEPT   tcp -- 0.0.0.0/0      0.0.0.0/0      tcp spt:80 state ESTABLISHED</code>
</div>
<div class="line number16 index15 alt1">
<code class="plain plain">ACCEPT   udp -- 0.0.0.0/0      0.0.0.0/0      udp dpt:53</code>
</div>
<div class="line number17 index16 alt2">
<code class="plain plain">ACCEPT   udp -- 0.0.0.0/0      0.0.0.0/0      udp spt:53</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
可以测试一下是否 DNS 可以通过iptables 了。</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_568872">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
<div class="line number5 index4 alt2">
5</div>
<div class="line number6 index5 alt1">
6</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain"></code><code class="bash comments">#hostwww.google.com</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">www.google.comis an </code><code class="bash functions">alias</code> <code class="bash plain">forwww.l.google.com.</code>
</div>
<div class="line number3 index2 alt2">
<code class="bash plain">www.l.google.comis an </code><code class="bash functions">alias</code> <code class="bash keyword">for</code> <code class="bash plain">www-china.l.google.com.</code>
</div>
<div class="line number4 index3 alt1">
<code class="bash plain">www-china.l.google.com has address 64.233.189.104</code>
</div>
<div class="line number5 index4 alt2">
<code class="bash plain">www-china.l.google.com has address 64.233.189.147</code>
</div>
<div class="line number6 index5 alt1">
<code class="bash plain">www-china.l.google.com has address 64.233.189.99</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
正常可以解析 google 域名。</p>
<p>
ping 方面可能还要设置些东西。</p>
<p>
用 nslookup 看看吧</p>
<p>
</p>
<div class="codetitle">
<span><u>复制代码</u></span> 代码如下:</div>
<div class="codebody" id="code72431">
<br>
#nslookup >www.google.com Server: 192.168.1.1 Address: 192.168.1.1#53 Non-authoritative answer: www.google.comcanonical name =www.l.google.com. www.l.google.com canonical name = www-china.l.google.com. Name: www-china.l.google.com Address: 64.233.189.147 Name: www-china.l.google.com Address: 64.233.189.99 Name: www-china.l.google.com Address: 64.233.189.104</div>
<p>
</p>
<p>
说明本机DNS正常， iptables 允许53这个端口的访问。</p>
<p>
<strong>7、iptables对ftp的设置</strong></p>
<p>
现在我开始对ftp端口的设置，按照我们以前的视频，添加需要开放的端口</p>
<p>
ftp连接端口有2个 21 和 20 端口，我现在添加对应的规则。</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_227779">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain"></code><code class="bash comments">#iptables -A INPUT -p tcp --dport 21 -j ACCEPT</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain"></code><code class="bash comments">#iptables -A INPUT -p tcp --dport 20 -j ACCEPT</code>
</div>
<div class="line number3 index2 alt2">
<code class="bash plain"></code><code class="bash comments">#iptables -A OUTPUT -p tcp --sport 21 -j ACCEPT</code>
</div>
<div class="line number4 index3 alt1">
<code class="bash plain"></code><code class="bash comments">#iptables -A OUTPUT -p tcp --sport 20 -j ACCEPT</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
好，这样就添加完了，我们用浏览器访问一下ftp,出现超时。</p>
<p>
所以我刚才说 ftp 是比较特殊的端口，它还有一些端口是数据传输端口，例如目录列表，上传，下载文件都要用到这些端口。<br>
而这些端口是任意端口。。。这个任意真的比较特殊。如果不指定什么一个端口范围， iptables 很难对任意端口开放的，<br>
如果iptables允许任意端口访问，那和不设置防火墙没什么区别，所以不现实的。那么我们的解决办法就是指定这个数据传输端口的一个范围。</p>
<p>
下面我们修改一下ftp配置文件。</p>
<p>
我这里使用vsftpd来修改演示，其他ftp我不知道哪里修改，大家可以找找资料。</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_624736">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain"></code><code class="bash comments">#vi /etc/vsftpd.conf</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
在配置文件的最下面加入</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterplain" id="highlighter_947913">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="plain plain">pasv_min_port=30001</code>
</div>
<div class="line number2 index1 alt1">
<code class="plain plain">pasv_max_port=31000</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
然后保存退出。</p>
<p>
这两句话的意思告诉vsftpd, 要传输数据的端口范围就在30001到31000 这个范围内传送。</p>
<p>
这样我们使用 iptables 就好办多了，我们就打开 30001到31000 这些端口。</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_819082">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain"></code><code class="bash comments">#iptables -A INPUT -p tcp --dport 30001:31000 -j ACCEPT</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain"></code><code class="bash comments">#iptables -A OUTPUT -p tcp --sport 30001:31000 -j ACCEPT</code>
</div>
<div class="line number3 index2 alt2">
<code class="bash plain"></code><code class="bash comments">#service iptables save</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
最后进行保存，然后我们再用浏览器范围下 ftp。可以正常访问</p>
<p>
用个账号登陆上去，也没有问题，上传一些文件上去看看。</p>
<p>
上传和下载都正常。再查看下 iptables 的设置</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_95018">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain"></code><code class="bash comments">#iptables -L -n</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<div class="jb51code">
<div>
<div class="syntaxhighlighterplain" id="highlighter_794278">
<div class="toolbar">
<span>?</span>
</div>
<table border="0" cellpadding="0" cellspacing="0"><tbody><tr>
<td class="gutter">
<div class="line number1 index0 alt2">
1</div>
<div class="line number2 index1 alt1">
2</div>
<div class="line number3 index2 alt2">
3</div>
<div class="line number4 index3 alt1">
4</div>
<div class="line number5 index4 alt2">
5</div>
<div class="line number6 index5 alt1">
6</div>
<div class="line number7 index6 alt2">
7</div>
<div class="line number8 index7 alt1">
8</div>
<div class="line number9 index8 alt2">
9</div>
<div class="line number10 index9 alt1">
10</div>
<div class="line number11 index10 alt2">
11</div>
<div class="line number12 index11 alt1">
12</div>
<div class="line number13 index12 alt2">
13</div>
<div class="line number14 index13 alt1">
14</div>
<div class="line number15 index14 alt2">
15</div>
<div class="line number16 index15 alt1">
16</div>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="plain plain">Chain INPUT (policy DROP)</code>
</div>
<div class="line number2 index1 alt1">
<code class="plain plain">target   prot opt source        destination</code>
</div>
<div class="line number3 index2 alt2">
<code class="plain plain">ACCEPT   tcp -- 0.0.0.0/0      0.0.0.0/0     tcp dpt:22</code>
</div>
<div class="line number4 index3 alt1">
<code class="plain plain">ACCEPT   tcp -- 0.0.0.0/0      0.0.0.0/0     tcp dpt:21</code>
</div>
<div class="line number5 index4 alt2">
<code class="plain plain">ACCEPT   tcp -- 0.0.0.0/0      0.0.0.0/0     tcp dpt:20</code>
</div>
<div class="line number6 index5 alt1">
<code class="plain plain">ACCEPT   tcp -- 0.0.0.0/0      0.0.0.0/0     tcp dpts:30001:31000</code>
</div>
<div class="line number7 index6 alt2">
</div>
<div class="line number8 index7 alt1">
<code class="plain plain">Chain FORWARD (policy DROP)</code>
</div>
<div class="line number9 index8 alt2">
<code class="plain plain">target   prot opt source        destination</code>
</div>
<div class="line number10 index9 alt1">
</div>
<div class="line number11 index10 alt2">
<code class="plain plain">Chain OUTPUT (policy DROP)</code>
</div>
<div class="line number12 index11 alt1">
<code class="plain plain">target   prot opt source        destination</code>
</div>
<div class="line number13 index12 alt2">
<code class="plain plain">ACCEPT   tcp -- 0.0.0.0/0      0.0.0.0/0     tcp spt:22</code>
</div>
<div class="line number14 index13 alt1">
<code class="plain plain">ACCEPT   tcp -- 0.0.0.0/0      0.0.0.0/0     tcp spt:21</code>
</div>
<div class="line number15 index14 alt2">
<code class="plain plain">ACCEPT   tcp -- 0.0.0.0/0      0.0.0.0/0     tcp spt:20</code>
</div>
<div class="line number16 index15 alt1">
<code class="plain plain">ACCEPT   tcp -- 0.0.0.0/0      0.0.0.0/0     tcp spts:30001:31000</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
这是我为了演示ftp特殊端口做的简单规则，大家可以添加一些对数据包的验证</p>
<p>
例如 -m state --state ESTABLISHED,RELATED 等等要求更加高的验证</p>
<p>
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。</p>
<p>
原文链接：http://www.cnblogs.com/zongfa/p/7967935.html</p>

頁: [1]

琼殿技术论坛's Archiver

Linux下iptables 禁止端口和开放端口示例