php如何判断IP为有效IP地址【转】

不需要正则表达式来判断，因为在php5.2.0之后，有专门的函数来做这个判断了。

1、判断是否是合法IP

if(filter_var($ip, FILTER_VALIDATE_IP)) {// it's valid}else {// it's not valid}

2、判断是否是合法的IPv4 IP地址

if(filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4)) {// it's valid}else {// it's not valid}

3、判断是否是合法的公共IPv4地址，192.168.1.1这类的私有IP地址将会排除在外

if(filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_IPV4 | FILTER_FLAG_NO_PRIV_RANGE)) {// it's valid}else {// it's not valid}

4、判断是否是合法的IPv6地址

if(filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_RES_RANGE)) {// it's valid}else {// it's not valid}

5、判断是否是public IPv4 IP或者是合法的Public IPv6 IP地址

if(filter_var($ip, FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE)) {// it's valid}else {// it's not valid}

文章转自:https://www.cnblogs.com/caicaizi/p/8043791.html