Its prototype
follows:
int checkdnsrr(string host [, string type])
CHAPTER 16 ?– NETWORKING 403
DNS records are checked based on the supplied host value and optional DNS
resource record type, returning TRUE if any records are located, and FALSE otherwise.
Possible record types include the following:
A: IPv4 Address Record. Responsible for the hostname-to-IPv4 address translation.
AAAA: IPv6 Address Record. Responsible for the hostname-to-IPv6 address
translation.
A6: IPv6 Address Record. Used to represent IPv6 addresses. Intended to supplant
present use of AAAA records for IPv6 mappings.
ANY: Looks for any type of record.
CNAME: Canonical Name Record. Maps an alias to the real domain name.
MX: Mail Exchange Record. Determines the name and relative preference of a
mail server for the host. This is the default setting.
NAPTR: Naming Authority Pointer. Allows for non-DNS-compliant names,
resolving them to new domains using regular expression rewrite rules. For
example, an NAPTR might be used to maintain legacy (pre-DNS) services.
NS: Name Server Record. Determines the name server for the host.
PTR: Pointer Record. Maps an IP address to a host.
SOA: Start of Authority Record. Sets global parameters for the host.
SRV: Services Record. Denotes the location of various services for the supplied
domain.
Consider an example. Suppose you want to verify whether the domain name
example.
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