Searches DNS for MX records corresponding to hostname.
The Internet host name.
A list of the MX records found is placed into the array hosts.
If the weights array is given, it will be filled with the weight information gathered.
Returns true if any records are found; returns false if no records were found or if an error occurred.
This function should not be used for the purposes of address verification. Only the mailexchangers found in DNS are returned, however, according to RFC 2821 when no mail exchangers are listed, hostname itself should be used as the only mail exchanger with a priority of 0.
For compatibility with Windows before this was implemented, then try the PEAR class Net_DNS.