Searches DNS for records of type type corresponding to hostname.
hostname may either be the IP address in dotted-quad notation or the host name.
type may be any one of: A, MX, NS, SOA, PTR, CNAME, AAAA, A6, SRV, NAPTR, TXT or ANY.
Returns true if any records are found; returns false if no records were found or if an error occurred.
For compatibility with Windows before this was implemented, then try the PEAR class Net_DNS.