IS_IPV4(expr)

Returns 1 if the argument is a valid IPv4 address specified as a string, 0 otherwise.

mysql> SELECT IS_IPV4('10.0.5.9'), IS_IPV4('10.0.5.256');
-> 1, 0
For a given argument, if IS_IPV4() returns 1, INET_ATON() (and INET6_ATON()) will return non-NULL. The converse statement is not true: In some cases, INET_ATON() returns non-NULL when IS_IPV4() returns 0.

As implied by the preceding remarks, IS_IPV4() is more strict than INET_ATON() about what constitutes a valid IPv4 address, so it may be useful for applications that need to perform strong checks against invalid values. Alternatively, use INET6_ATON() to convert IPv4 addresses to internal form and check for a NULL result (which indicates an invalid address). INET6_ATON() is equally strong as IS_IPV4() about checking IPv4 addresses.

This function was added in MySQL 5.6.3.