(PHP 3, PHP 4 >= 4.0.0)checkdnsrr -- Check DNS records corresponding to a given Internet host name or IP address
Searches DNS for records of type type corresponding to host. Returns TRUE if any records are found; returns FALSE if no records were found or if an error occurred.
type may be any one of: A, MX, NS, SOA, PTR, CNAME, or ANY. The default is MX.
Host may either be the IP address in dotted-quad notation or the host name.
checkdnsrr() is not available on windows.