Searches DNS for MX records corresponding to
hostname. Returns TRUE if any records are
found; returns FALSE if no records were found or if an error
A list of the MX records found is placed into the array
mxhosts. If the
weight array is given, it will be filled
with the weight information gathered.
Note: 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,
hostnameitself should be used as the only mail exchanger with a priority of 0.