Checks whether the IP address presents a network address.
Syntax
public static function netaddr ($netaddr, $netmask)
Parameters
netaddr
A string value that specifies the IP address to check.
netmask
A string value with a subnet mask to be used for a checkup.
Returns
A boolean which is true if the IP address presents a network address, false otherwise.
Remarks
A valid format of an IP address or an IP mask is a dotted-decimal notation (xxx.xxx.xxx.xxx).