CentOS---常用网络配置详解
<p><strong>一、配置文件详解</strong></p>
<p>
在RHEL或者CentOS等Redhat系的Linux系统里，跟网络有关的主要设置文件如下：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_974550">
<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>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain">/etc/host</code><code class="bash plain">.conf 配置域名服务客户端的控制文件</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">/etc/hosts</code> <code class="bash plain">完成主机名映射为IP地址的功能</code>
</div>
<div class="line number3 index2 alt2">
<code class="bash plain">/etc/resolv</code><code class="bash plain">.conf 域名服务客户端的配置文件,用于指定域名服务器的位置</code>
</div>
<div class="line number4 index3 alt1">
<code class="bash plain">/etc/sysconfig/network</code> <code class="bash plain">包含了主机最基本的网络信息,用于系统启动.</code>
</div>
<div class="line number5 index4 alt2">
<code class="bash plain">/etc/sysconfig/network-script/</code> <code class="bash plain">系统启动时初始化网络的一些信息</code>
</div>
<div class="line number6 index5 alt1">
<code class="bash plain">/etc/xinetd</code><code class="bash plain">.conf 定义了由超级进程xinetd启动的网络服务</code>
</div>
<div class="line number7 index6 alt2">
<code class="bash plain">/etc/networks</code> <code class="bash plain">完成域名与网络地址的映射</code>
</div>
<div class="line number8 index7 alt1">
<code class="bash plain">/etc/protocols</code> <code class="bash plain">设定了主机使用的协议以及各个协议的协议号</code>
</div>
<div class="line number9 index8 alt2">
<code class="bash plain">/etc/services</code> <code class="bash plain">设定主机的不同端口的网络服务</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
1. /etc/host.conf文件的默认信息如下：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_322244">
<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">multi on </code><code class="bash comments">#允许主机拥有多个IP地址</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">order hosts,bind </code><code class="bash comments">#主机名解析顺序，即本地解析,DNS域名解析的顺序</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
这个文件一般不需要我们修改，默认的解析顺序是本地解析,DNS服务器解析，也就是说在本系统里对于一个主机名首先进行本地解析，如果本地解析没有，然后进行DNS服务器解析。</p>
<p>
2. /etc/hosts文件默认的内容大概如下：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_350538">
<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">127.0.0.1 butbueatiful localhost.localdomain localhost</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">::1 localhost6.localdomain6 localhost6</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
可见，默认的情况是本机ip和本机一些主机名的对应关系，第一行是ipv4信息，第二行是ipv6信息，如果用不上ipv6本机解析，一般把该行注释掉。</p>
<p>
第一行的解析效果是，butbueatiful localhost.localdomain localhost都会被解析成127.0.0.1,我们可以用ping试试。</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_509319">
<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"># ping -c 3 butbueatiful</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">PING butbueatiful (127.0.0.1) 56(84) bytes of data.</code>
</div>
<div class="line number3 index2 alt2">
<code class="bash plain">64 bytes from butbueatiful (127.0.0.1): icmp_seq=1 ttl=64 </code><code class="bash functions">time</code><code class="bash plain">=0.061 ms</code>
</div>
<div class="line number4 index3 alt1">
<code class="bash plain">64 bytes from butbueatiful (127.0.0.1): icmp_seq=2 ttl=64 </code><code class="bash functions">time</code><code class="bash plain">=0.052 ms</code>
</div>
<div class="line number5 index4 alt2">
<code class="bash plain">64 bytes from butbueatiful (127.0.0.1): icmp_seq=3 ttl=64 </code><code class="bash functions">time</code><code class="bash plain">=0.051 ms</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
--- butbueatiful ping statistics ---<br>
3 packets transmitted, 3 received, 0% packet loss, time 1999ms<br>
rtt min/avg/max/mdev = 0.051/0.054/0.061/0.009 ms</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_412909">
<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"># ping -c 3 localhost.localdomain</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">PING butbueatiful (127.0.0.1) 56(84) bytes of data.</code>
</div>
<div class="line number3 index2 alt2">
<code class="bash plain">64 bytes from butbueatiful (127.0.0.1): icmp_seq=1 ttl=64 </code><code class="bash functions">time</code><code class="bash plain">=0.055 ms</code>
</div>
<div class="line number4 index3 alt1">
<code class="bash plain">64 bytes from butbueatiful (127.0.0.1): icmp_seq=2 ttl=64 </code><code class="bash functions">time</code><code class="bash plain">=0.035 ms</code>
</div>
<div class="line number5 index4 alt2">
<code class="bash plain">64 bytes from butbueatiful (127.0.0.1): icmp_seq=3 ttl=64 </code><code class="bash functions">time</code><code class="bash plain">=0.050 ms</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
--- butbueatiful ping statistics ---<br>
3 packets transmitted, 3 received, 0% packet loss, time 1999ms<br>
rtt min/avg/max/mdev = 0.035/0.046/0.055/0.011 ms</p>
<p>
看到上面的结果，你可能会问为什么ping localhost.localdomain的时候，下面显示的是却是butbueatiful，这是因为第一个主机名butbueatiful后面的那些主机名其实都是butbueatiful的主机别名。</p>
<p>
如果我们要追加新的本地解析，比如我们希望在我们的机器里把yyyy.com和www.yyyy.com都解析成192.168.0.100，那么就追加如下一句即可：</p>
<p>
192.168.0.100 yyyy.com www.yyyy.com</p>
<p>
同样，在这里，www.yyyy.com是yyyy.com的主机别名。</p>
<p>
如果你仔细一想，会发现，其实这个文件是很危险的，如果有人恶意修改了你这个文件，比如把淘宝的网站域名解析到了他的钓鱼网站，那你就要中招了。</p>
<p>
3. /etc/resolv.conf, 指定域名解析的DNS服务器IP等信息, 配置参数一般接触到的有4个：</p>
<ul>
<li>
nameserver 指定DNS服务器的IP地址</li>
<li>
domain 定义本地域名信息</li>
<li>
search 定义域名的搜索列表</li>
<li>
sortlist 对gethostbyname返回的地址进行排序</li>
</ul>
<p>
但是最常用的配置参数是nameserver，其他的可以不设置，这个参数指定了DNS服务器的IP地址，如果设置不正确，就无法进行正常的域名解析。</p>
<p>
一般来说，推荐设置2个DNS服务器，比如我们用google的免费DNS服务器，那么该文件的设置内容如下：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_434013">
<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">nameserver 8.8.8.8</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">nameserver 8.8.4.4</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
同样，这个文件也是危险的，如果被人恶意改成了他自己的DNS服务器，他就可以为所欲为的控制你通过域名访问的每个目的地了，这就是常说的DNS劫持。</p>
<p>
4. /etc/sysconfig/network, 典型的配置如下：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_321447">
<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">NETWORKING=</code><code class="bash functions">yes</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">NETWORKING_IPV6=no</code>
</div>
<div class="line number3 index2 alt2">
<code class="bash plain">HOSTNAME=butbueatiful</code>
</div>
<div class="line number4 index3 alt1">
<code class="bash plain">GATEWAY=192.168.0.1</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
参数简要解释： </p>
<ul>
<li>
NETWORK 设置网络是否有效，yes有效，no无效</li>
<li>
NETWORKING_IPV6 设置ipv6网络是否有效，yes有效，no无效</li>
<li>
HOSTNAME 设置服务器的主机名，最好和/etc/hosts里设置一样，否则在使用一些程序的时候会有问题。</li>
<li>
GATEWAY 指定默认网关IP</li>
</ul>
<p>
5. ifcfg-ethX, 设置对应网口的IP等信息, 比如第一个网口, 那么就是/etc/sysconfig/network-scripts/ifcfg-eth0，配置例子：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_506863">
<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>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash plain">DEVICE=</code><code class="bash string">"eth0"</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">BOOTPROTO=</code><code class="bash string">"static"</code>
</div>
<div class="line number3 index2 alt2">
<code class="bash plain">BROADCAST=</code><code class="bash string">"192.168.0.255"</code>
</div>
<div class="line number4 index3 alt1">
<code class="bash plain">HWADDR=</code><code class="bash string">"00:16:36:1B:BB:74"</code>
</div>
<div class="line number5 index4 alt2">
<code class="bash plain">IPADDR=</code><code class="bash string">"192.168.0.100"</code>
</div>
<div class="line number6 index5 alt1">
<code class="bash plain">NETMASK=</code><code class="bash string">"255.255.255.0"</code>
</div>
<div class="line number7 index6 alt2">
<code class="bash plain">ONBOOT=</code><code class="bash string">"yes"</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
参数简要解释：</p>
<ul>
<li>
DEVICE 设备名，不要自己乱改，和文件ifcfg-ethX里的ethX要一致</li>
<li>
BROADCAST 广播地址</li>
<li>
HWADDR 物理地址，这个你不要乱改</li>
<li>
IPADDR IP地址</li>
<li>
NETMASK 子网掩码</li>
<li>
ONBOOT 启动或者重启网络时，是否启动该设备，yes是启动，no是不启动</li>
<li>
BOOTPROTO 开机协议，最常见的三个参数如下：</li>
</ul>
<p>
①static(静态IP)</p>
<p>
② none(不指定,设置固定ip的情况，这个也行，但是如果要设定多网口绑定bond的时候，必须设成none）</p>
<p>
③dhcp(动态获得IP相关信息）</p>
<p>
6. route-ethX,比如第一个网口eth0的路由信息,那么就是/etc/sysconfig/network-scripts/route-eth0：</p>
<p>
比如我们现在有这样一个需求，通过eth0去网络172.17.27.0/24不走默认路由，需要走192.168.0.254，那么我们第一反应，肯定是用route命令追加路由信息：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_428959">
<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"># route add -net 172.17.27.0 netmask 255.255.255.0 gw 192.168.0.254 dev eth0</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
可是，你没意识到的是，这样只是动态追加的而已，重启网络后，路由信息就消失了，所以需要设置静态路由，这时候就要设置/etc/sysconfig/network-scripts/route-eth0文件了，如果没有该文件，你就新建一个：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_695359">
<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"># vi /etc/sysconfig/network-scripts/route-eth0</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash comments">#追加</code>
</div>
<div class="line number3 index2 alt2">
<code class="bash plain">172.17.27.0</code><code class="bash plain">/24via</code> <code class="bash plain">192.168.0.254</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
这下即使重启网络，重启系统，该路由也会自动加载，当然了，如果你没有这样的需要，那么这个文件就没必要创建和配置了。</p>
<p>
<strong>二、常用的网络配置</strong></p>
<p>
伴随着时间的推移Red Hat公司推出了RHEL6.2，随后CentOS也紧随其后退出了CentOS6.2。新的系统中厂商加入了大量虚拟化及云计算的元素，同时对于细节的改变也不少，这里我们仅对新系统中的网络参数做以详尽说明。</p>
<p>
Linux中网络参数大致包含以下内容：</p>
<ul>
<li>
IP地址</li>
<li>
子网掩码</li>
<li>
网关</li>
<li>
DNS服务器</li>
<li>
主机名</li>
</ul>
<p>
历来Linux系统中修改这些参数的方式通常有：命令、文件两种。其中通过命令设置可以立即生效但重启后将失效，通过文件修改实现永久生效，但不会立即生效。</p>
<p>
首先我们来看看命令的方式：</p>
<ul>
<li>
ifconfig：查看与设置IP地址、子网掩码</li>
<li>
hostname：查看与设置主机名</li>
<li>
route： 查看与设置路由信息（默认网关等）</li>
</ul>
<p>
通过文件的方式修改：</p>
<p>
/etc/sysconfig/network-scripts/ifcfg-设备名（通常为ifcfg-eth0)</p>
<p>
/etc/sysconfig/network</p>
<p>
/etc/resolv.conf文件：设置DNS服务器</p>
<p>
以上种种这些方式可以同时在5.0与6.0系统中实现，但6.0系统后官方文档中描述说：ifconfig与route是非常陈旧的命令，取而代之的是ip命令。</p>
<p>
那么我们先看一下老的命令使用方式：</p>
<p>
*************************************************************************</p>
<p>
ifconfig 接口 选项|地址</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_755869">
<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>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash comments"># ifconfig eth0 up # 开启eth0网卡</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash comments"># ifconfig eth0 down # 关闭eth0网卡</code>
</div>
<div class="line number3 index2 alt2">
<code class="bash comments"># ifconfig eth0 -arp # 关闭eth0网卡arp协议</code>
</div>
<div class="line number4 index3 alt1">
<code class="bash comments"># ifconfig eth0 promisc # 开启eth0网卡的混合模式</code>
</div>
<div class="line number5 index4 alt2">
<code class="bash comments"># ifconfig eth0 mtu 1400 # 设置eth0网卡的最大传输单元为1400</code>
</div>
<div class="line number6 index5 alt1">
<code class="bash comments"># ifconfig eth0 192.168.0.2/24 # 设置eth0网卡IP地址</code>
</div>
<div class="line number7 index6 alt2">
<code class="bash comments"># ifconfig eth0 192.168.0.2 netmask 255.255.255.0 # 功能同上</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
*************************************************************************<br>
主机名：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_55174">
<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 comments"># hostname # 查看主机名</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash comments"># hostname butbueatiful.com # 设置主机名为butbueatiful.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>
*************************************************************************<br>
网关设置：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_51263">
<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">route add [-net|-host] target gw</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">route del [-net|-host] target gw</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_811131">
<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="bash comments"># route add -net 192.168.3.0/24 gw 192.168.0.254 # 设置到192.168.3.0网段的网关为192.168.0.254</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash comments"># route add -net 192.168.3.0 netmask 255.255.255.0 gw 192.168.0.254 # 功能同上</code>
</div>
<div class="line number3 index2 alt2">
<code class="bash comments"># route add -host 192.168.4.4 gw 192.168.0.254 # 设置到192.168.4.4主机的网关为192.168.0.254</code>
</div>
<div class="line number4 index3 alt1">
<code class="bash comments"># </code>
</div>
<div class="line number5 index4 alt2">
<code class="bash comments"># route del -net 192.168.3.0/24 # 删除192.168.3.0网段的网关信息</code>
</div>
<div class="line number6 index5 alt1">
<code class="bash comments"># route del -host 192.168.4.4 # 删除192.168.4.4主机的网关信息</code>
</div>
<div class="line number7 index6 alt2">
<code class="bash comments"># route add default gw 192.168.0.254 # 设置默认网关为192.168.0.254</code>
</div>
<div class="line number8 index7 alt1">
<code class="bash comments"># route del default gw 192.168.0.254 # 删除默认网关为192.168.0.254</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
*************************************************************************</p>
<p>
而如今官方不再推荐使用如此陈旧的命令而推荐使用 ip 这个命令，以下我们看看它的用法：</p>
<p>
ip [选项] 操作对象{link|addr|route...}</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_481396">
<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="bash comments"># ip link show # 显示网络接口信息</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash comments"># ip link set eth0 upi # 开启网卡</code>
</div>
<div class="line number3 index2 alt2">
<code class="bash comments"># ip link set eth0 down # 关闭网卡</code>
</div>
<div class="line number4 index3 alt1">
<code class="bash comments"># ip link set eth0 promisc on # 开启网卡的混合模式</code>
</div>
<div class="line number5 index4 alt2">
<code class="bash comments"># ip link set eth0 promisc offi # 关闭网卡的混个模式</code>
</div>
<div class="line number6 index5 alt1">
<code class="bash comments"># ip link set eth0 txqueuelen 1200 # 设置网卡队列长度</code>
</div>
<div class="line number7 index6 alt2">
<code class="bash comments"># ip link set eth0 mtu 1400 # 设置网卡最大传输单元</code>
</div>
<div class="line number8 index7 alt1">
<code class="bash comments"># ip addr show # 显示网卡IP信息</code>
</div>
<div class="line number9 index8 alt2">
<code class="bash comments"># ip addr add 192.168.0.1/24 dev eth0 # 设置eth0网卡IP地址192.168.0.1</code>
</div>
<div class="line number10 index9 alt1">
<code class="bash comments"># ip addr del 192.168.0.1/24 dev eth0 # 删除eth0网卡IP地址</code>
</div>
<div class="line number11 index10 alt2">
</div>
<div class="line number12 index11 alt1">
<code class="bash comments"># ip route list # 查看路由信息</code>
</div>
<div class="line number13 index12 alt2">
<code class="bash comments"># ip route add 192.168.4.0/24 via 192.168.0.254 dev eth0 # 设置192.168.4.0网段的网关为192.168.0.254,数据走eth0接口</code>
</div>
<div class="line number14 index13 alt1">
<code class="bash comments"># ip route add default via 192.168.0.254 dev eth0 # 设置默认网关为192.168.0.254</code>
</div>
<div class="line number15 index14 alt2">
<code class="bash comments"># ip route del 192.168.4.0/24 # 删除192.168.4.0网段的网关</code>
</div>
<div class="line number16 index15 alt1">
<code class="bash comments"># ip route del default # 删除默认路由</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
**************************************************************<br>
接下来再看看通过文件修改网络参数：（CentOS6.2系统为例）</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_474954">
<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>
</td>
<td class="code">
<div class="container">
<div class="line number1 index0 alt2">
<code class="bash comments"># cat /etc/sysconfig/network-scripts/ifcfg-eth0 </code>
</div>
<div class="line number2 index1 alt1">
</div>
<div class="line number3 index2 alt2">
<code class="bash plain">DEVICE=</code><code class="bash string">"eth0"</code> <code class="bash plain">设备名</code>
</div>
<div class="line number4 index3 alt1">
<code class="bash plain">NM_CONTROLLED=</code><code class="bash string">"yes"</code> <code class="bash plain">设备是否被NetworkManager管理</code>
</div>
<div class="line number5 index4 alt2">
<code class="bash plain">ONBOOT=</code><code class="bash string">"no"</code> <code class="bash plain">开机是否启动</code>
</div>
<div class="line number6 index5 alt1">
<code class="bash plain">HWADDR=</code><code class="bash string">"00:0C:29:59:E2:D3"</code> <code class="bash plain">硬件地址（MAC地址）</code>
</div>
<div class="line number7 index6 alt2">
<code class="bash plain">TYPE=Ethernet 类型</code>
</div>
<div class="line number8 index7 alt1">
<code class="bash plain">BOOTPROTO=none 启动协议{none|dhcp}</code>
</div>
<div class="line number9 index8 alt2">
<code class="bash plain">IPADDR=192.168.0.1 IP地址</code>
</div>
<div class="line number10 index9 alt1">
<code class="bash plain">PREFIX=24 子网掩码</code>
</div>
<div class="line number11 index10 alt2">
<code class="bash plain">GATEWAY=192.168.0.254 默认网关</code>
</div>
<div class="line number12 index11 alt1">
<code class="bash plain">DNS1=202.106.0.20 主DNS</code>
</div>
<div class="line number13 index12 alt2">
<code class="bash plain">DOMAIN=202.106.46.151 辅助DNS</code>
</div>
<div class="line number14 index13 alt1">
<code class="bash plain">UUID=5fb06bd0-0bb0-7ffb-45f1-d6edd65f3e03 设备UUID编号</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
**************************************************************</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_538144">
<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 comments"># cat /etc/sysconfig/network</code>
</div>
<div class="line number2 index1 alt1">
</div>
<div class="line number3 index2 alt2">
<code class="bash plain">HOSTNAME=butbueatiful.com 主机名</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
**************************************************************</p>
<p>
注意：在5.0时代DNS服务器写在 /etc/resolv.conf 文件中，但到了6.0时代DNS可以写在/etc/resolv.conf但是此时需要在 /etc/sysconfig/network-scripts/ifcfg-eth0 文件中添加 PEERDNS=no 配置，不然每次重启网卡就会重写/etc/resolv.conf文件的内容，当然了也可以直接写在 /etc/sysconfig/network-scripts/ifcfg-eth0 文件中。</p>
<p>
后记：</p>
<p>
1. 配置/etc/resolv.confg重启丢失解决方法：</p>
<p>
一种方法是把 PEERDNS 设置为“no”。</p>
<p>
找到网卡配置文件，位置和： /etc/sysconfig/network-scripts/ifcfg-eth 文件中加入PEERDNS 选项。可以是 0, 1, 2等等，代表不同网卡的配置文件。例如，系统上第一张网卡是eth0的话，那它的配置文件就是/etc/sysconfig/network-scripts/ifcfg-eth0 然后在文件中把 PEERDNS 改为 ‘no'.</p>
<p>
例如：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_673218">
<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">DEVICE=eth0</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">BOOTPROTO=dhcp</code>
</div>
<div class="line number3 index2 alt2">
<code class="bash plain">ONBOOT=</code><code class="bash functions">yes</code>
</div>
<div class="line number4 index3 alt1">
<code class="bash plain">TYPE=Ethernet</code>
</div>
<div class="line number5 index4 alt2">
<code class="bash plain">PEERDNS=no</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
这个选项可令 /etc/resolv.conf 在系统重启后不会被重写。</p>
<p>
另一种方法是在这个文件中增加DNS：</p>
<p>
如：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_735795">
<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">DNS1=127.0.0.1</code>
</div>
<div class="line number2 index1 alt1">
<code class="bash plain">DNS2=8.8.8.8</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
2. 安全设置</p>
<p>
我们前面说了/etc/resolv.conf和/etc/hosts被人篡改了的话, 会很危险, 那我们在设置好着2个文件后, 做一下处理, 让这2个文件默认不能直接修改, 即使root也不行, 执行如下命令：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_889607">
<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"># chattr +i /etc/{resolv.conf,hosts}</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
如果我们自己想修改的时候，执行： </p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_307576">
<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"># chattr -i /etc/{resolv.conf,hosts}</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
然后就可以修改了，修改完了别忘记+i。</p>
<p>
3. 网络排除思路</p>
<p>
检查配置文件是否有错误(书写及语法错误等）</p>
<p>
检查本机网络协议是否正确：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_699938">
<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 comments"># ping -c 3 127.0.0.1</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
检查本机网卡链路是否正确：</p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_242811">
<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 comments"># ping -c 3 192.168.0.1(本机IP地址)</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
检查网关是否正确： </p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_804625">
<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 comments"># ping -c 3 192.168.0.254(网关IP地址)</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
检查外部连通性： </p>
<div class="jb51code">
<div>
<div class="syntaxhighlighterbash" id="highlighter_19560">
<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 comments"># ping -c 3 www.google.com.hk</code>
</div>
</div>
</td>
</tr></tbody></table>
</div>
</div>
<div class="codetool" id="codetool">
<div class="code_n">
<textarea></textarea>
</div>
</div>
</div>
<p>
检查硬件</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服务器之家。</p>
<p>
原文链接：http://blog.chinaunix.net/uid-26495963-id-3230810.html</p>
頁:
[1]