如何使用preg_match函数来验证IP地址，保证格式正确且有效？

gitbox 2025-08-27

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如何使用preg_match函数来验证IP地址，保证格式正确且有效？

在PHP中，`preg_match`函数是用来进行正则表达式匹配的一个非常强大的工具。当我们需要验证用户输入的IP地址是否格式正确时，`preg_match`可以快速完成这项任务。本文将详细讲解如何使用它验证IPv4和IPv6地址。

</span><span><span class="hljs-comment">### 1. IPv4地址验证</span></span><span>

IPv4地址由四段数字组成，每段数字的范围是</span><span><span class="hljs-number">0</span></span><span>到</span><span><span class="hljs-number">255</span></span><span>，中间用点号分隔，例如：</span><span><span class="hljs-number">192.168</span></span><span>.</span><span><span class="hljs-number">0.1</span></span><span>。为了确保格式和有效性，我们可以使用如下正则表达式：

```php
</span><span><span class="hljs-variable">$ipv4_pattern</span></span><span> = </span><span><span class="hljs-string">"/^((25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]?[0-9])\.){3}(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9]?[0-9])$/"</span></span><span>;
</span><span><span class="hljs-variable">$ip</span></span><span> = </span><span><span class="hljs-string">"192.168.1.100"</span></span><span>;

</span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-title function_ invoke__">preg_match</span></span><span>(</span><span><span class="hljs-variable">$ipv4_pattern</span></span><span>, </span><span><span class="hljs-variable">$ip</span></span><span>)) {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"IPv4地址格式正确"</span></span><span>;
} </span><span><span class="hljs-keyword">else</span></span><span> {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"IPv4地址格式不正确"</span></span><span>;
}
</span></span>

解释：

25[0-5] 匹配 250-255
2[0-4][0-9] 匹配 200-249
1[0-9]{2} 匹配 100-199
[1-9]?[0-9] 匹配 0-99
((...)\.){3}... 确保有四段数字且中间用点分隔

2. IPv6地址验证

IPv6地址格式更加复杂，由8组16进制数字组成，每组用冒号分隔。一个简单的正则表达式示例如下：

<span><span><span class="hljs-variable">$ipv6_pattern</span></span><span> = </span><span><span class="hljs-string">"/^([0-9a-fA-F]{1,4}:){7}[0-9a-fA-F]{1,4}$/"</span></span><span>;
</span><span><span class="hljs-variable">$ip</span></span><span> = </span><span><span class="hljs-string">"2001:0db8:85a3:0000:0000:8a2e:0370:7334"</span></span><span>;

</span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-title function_ invoke__">preg_match</span></span><span>(</span><span><span class="hljs-variable">$ipv6_pattern</span></span><span>, </span><span><span class="hljs-variable">$ip</span></span><span>)) {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"IPv6地址格式正确"</span></span><span>;
} </span><span><span class="hljs-keyword">else</span></span><span> {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"IPv6地址格式不正确"</span></span><span>;
}
</span></span>

3. 实用小技巧

如果你希望同时验证IPv4和IPv6，可以使用filter_var函数，它内置了IP验证功能：

<span><span><span class="hljs-keyword">if</span></span><span> (</span><span><span class="hljs-title function_ invoke__">filter_var</span></span><span>(</span><span><span class="hljs-variable">$ip</span></span><span>, FILTER_VALIDATE_IP)) {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"IP地址有效"</span></span><span>;
} </span><span><span class="hljs-keyword">else</span></span><span> {
    </span><span><span class="hljs-keyword">echo</span></span><span> </span><span><span class="hljs-string">"IP地址无效"</span></span><span>;
}
</span></span>

在处理用户输入时，始终注意去除空格和无效字符，避免因前后空格导致匹配失败：

<span><span><span class="hljs-variable">$ip</span></span><span> = </span><span><span class="hljs-title function_ invoke__">trim</span></span><span>(</span><span><span class="hljs-variable">$ip</span></span><span>);
</span></span>

对于大量IP地址的批量验证，可以结合循环和preg_match，高效检查每一个输入。

总结

使用preg_match结合精确的正则表达式，可以验证IP地址格式是否正确且有效。对于IPv4，重点在于数字范围和段数；对于IPv6，重点在于十六进制组和冒号分隔。掌握这些技巧，能够让你的PHP程序在处理网络地址时更加安全和可靠。

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