DNS_GET_RECORD(3) 1 DNS_GET_RECORD(3)
dns_get_record - Fetch DNS Resource Records associated with a hostname
SYNOPSIS
array dns_get_record (string $hostname, [int $type = DNS_ANY], [array &$authns], [array &$addtl], [bool &$raw = false])
DESCRIPTION
Fetch DNS Resource Records associated with the given $hostname.
PARAMETERS
o $hostname
-$hostname should be a valid DNS hostname such as " www.example.com". Reverse lookups can be generated using in-addr.arpa nota-
tion, but gethostbyaddr(3) is more suitable for the majority of reverse lookups.
Note
Per DNS standards, email addresses are given in user.host format (for example: hostmaster.example.com as opposed to hostmas-
ter@example.com), be sure to check this value and modify if necessary before using it with a functions such as mail(3).
o $type
- By default, dns_get_record(3) will search for any resource records associated with $hostname. To limit the query, specify the
optional $type parameter. May be any one of the following: DNS_A, DNS_CNAME, DNS_HINFO, DNS_MX, DNS_NS, DNS_PTR, DNS_SOA, DNS_TXT,
DNS_AAAA, DNS_SRV, DNS_NAPTR, DNS_A6, DNS_ALL or DNS_ANY.
Note
Because of eccentricities in the performance of libresolv between platforms, DNS_ANY will not always return every record,
the slower DNS_ALL will collect all records more reliably.
o $authns
- Passed by reference and, if given, will be populated with Resource Records for the Authoritative Name Servers.
o $addtl
- Passed by reference and, if given, will be populated with any Additional Records.
o $raw
- In case of raw mode, we query only the requestd type instead of looping type by type before going with the additional info
stuff.
RETURN VALUES
This function returns an array of associative arrays, or FALSE on failure. Each associative array contains at minimum the following keys:
Basic DNS attributes
+----------+---------------------------------------------------+
|Attribute | |
| | |
| | Meaning |
| | |
+----------+---------------------------------------------------+
| host | |
| | |
| | The record in the DNS namespace to which the |
| | rest of the associated data refers. |
| | |
| class | |
| | |
| | dns_get_record(3) only returns Internet class |
| | records and as such this parameter will always |
| | return IN. |
| | |
| type | |
| | |
| | String containing the record type. Additional |
| | attributes will also be contained in the result- |
| | ing array dependant on the value of type. See ta- |
| | ble below. |
| | |
| ttl | |
| | |
| | |
| | "Time To Live" remaining for this record. This |
| | will not equal the record's original ttl, but |
| | will rather equal the original ttl minus whatever |
| | length of time has passed since the authoritative |
| | name server was queried. |
| | |
+----------+---------------------------------------------------+
Other keys in associative arrays dependant on 'type'
+-----------------+---------------------------------------------------+
| Type | |
| | |
| | Extra Columns |
| | |
+-----------------+---------------------------------------------------+
| | |
| A | |
| | |
| | |
| | ip: An IPv4 addresses in dotted decimal notation. |
| | |
| | |
| MX | |
| | |
| | |
| | pri: Priority of mail exchanger. Lower numbers |
| | indicate greater priority. target: FQDN of the |
| | mail exchanger. See also dns_get_mx(3). |
| | |
| | |
| CNAME | |
| | |
| | |
| | target: FQDN of location in DNS namespace to |
| | which the record is aliased. |
| | |
| | |
| NS | |
| | |
| | |
| | target: FQDN of the name server which is authori- |
| | tative for this hostname. |
| | |
| | |
| PTR | |
| | |
| | |
| | target: Location within the DNS namespace to |
| | which this record points. |
| | |
| | |
| TXT | |
| | |
| | |
| | txt: Arbitrary string data associated with this |
| | record. |
| | |
| | |
| HINFO | |
| | |
| | |
| | cpu: IANA number designating the CPU of the |
| | machine referenced by this record. os: IANA num- |
| | ber designating the Operating System on the |
| | machine referenced by this record. See IANA's |
| | Operating System Names for the meaning of these |
| | values. |
| | |
| | |
| SOA | |
| | |
| | |
| | mname: FQDN of the machine from which the |
| | resource records originated. rname: Email |
| | address of the administrative contain for this |
| | domain. serial: Serial # of this revision of the |
| | requested domain. refresh: Refresh interval |
| | (seconds) secondary name servers should use when |
| | updating remote copies of this domain. retry: |
| | Length of time (seconds) to wait after a failed |
| | refresh before making a second attempt. expire: |
| | Maximum length of time (seconds) a secondary DNS |
| | server should retain remote copies of the zone |
| | data without a successful refresh before discard- |
| | ing. minimum-ttl: Minimum length of time (sec- |
| | onds) a client can continue to use a DNS resolu- |
| | tion before it should request a new resolution |
| | from the server. Can be overridden by individual |
| | resource records. |
| | |
| | |
| AAAA | |
| | |
| | |
| | ipv6: IPv6 address |
| | |
| | |
|A6(PHP >= 5.1.0) | |
| | |
| | |
| | masklen: Length (in bits) to inherit from the |
| | target specified by $chain. ipv6: Address for |
| | this specific record to merge with $chain. |
| | chain: Parent record to merge with $ipv6 data. |
| | |
| | |
| SRV | |
| | |
| | |
| | pri: (Priority) lowest priorities should be used |
| | first. weight: Ranking to weight which of com- |
| | monly prioritized $targets should be chosen at |
| | random. target and port: hostname and port where |
| | the requested service can be found. For addi- |
| | tional information see: RFC 2782 |
| | |
| | |
| NAPTR | |
| | |
| | |
| | order and pref: Equivalent to $pri and $weight |
| | above. flags, services, regex, and replacement: |
| | Parameters as defined by RFC 2915. |
| | |
+-----------------+---------------------------------------------------+
CHANGELOG
+--------+---------------------------------------------------+
|Version | |
| | |
| | Description |
| | |
+--------+---------------------------------------------------+
| 5.4.0 | |
| | |
| | Added $raw parameter. |
| | |
| 5.3.0 | |
| | |
| | This function is now available on Windows plat- |
| | forms. |
| | |
| 5.3.0 | |
| | |
| | Prior to this release, if the $authns parameter |
| | was given, the $addtl parameter was also |
| | required. |
| | |
+--------+---------------------------------------------------+
EXAMPLES
Example #1
Using dns_get_record(3)
<?php
$result = dns_get_record("php.net");
print_r($result);
?>
The above example will output something similar to:
Array
(
[0] => Array
(
[host] => php.net
[type] => MX
[pri] => 5
[target] => pair2.php.net
[class] => IN
[ttl] => 6765
)
[1] => Array
(
[host] => php.net
[type] => A
[ip] => 64.246.30.37
[class] => IN
[ttl] => 8125
)
)
Example #2
Using dns_get_record(3) and DNS_ANY
Since it's very common to want the IP address of a mail server once the MX record has been resolved, dns_get_record(3) also returns
an array in $addtl which contains associate records. $authns is returned as well containing a list of authoritative name servers.
<?php
/* Request "ANY" record for php.net,
and create $authns and $addtl arrays
containing list of name servers and
any additional records which go with
them */
$result = dns_get_record("php.net", DNS_ANY, $authns, $addtl);
echo "Result = ";
print_r($result);
echo "Auth NS = ";
print_r($authns);
echo "Additional = ";
print_r($addtl);
?>
The above example will output something similar to:
Result = Array
(
[0] => Array
(
[host] => php.net
[type] => MX
[pri] => 5
[target] => pair2.php.net
[class] => IN
[ttl] => 6765
)
[1] => Array
(
[host] => php.net
[type] => A
[ip] => 64.246.30.37
[class] => IN
[ttl] => 8125
)
)
Auth NS = Array
(
[0] => Array
(
[host] => php.net
[type] => NS
[target] => remote1.easydns.com
[class] => IN
[ttl] => 10722
)
[1] => Array
(
[host] => php.net
[type] => NS
[target] => remote2.easydns.com
[class] => IN
[ttl] => 10722
)
[2] => Array
(
[host] => php.net
[type] => NS
[target] => ns1.easydns.com
[class] => IN
[ttl] => 10722
)
[3] => Array
(
[host] => php.net
[type] => NS
[target] => ns2.easydns.com
[class] => IN
[ttl] => 10722
)
)
Additional = Array
(
[0] => Array
(
[host] => pair2.php.net
[type] => A
[ip] => 216.92.131.5
[class] => IN
[ttl] => 6766
)
[1] => Array
(
[host] => remote1.easydns.com
[type] => A
[ip] => 64.39.29.212
[class] => IN
[ttl] => 100384
)
[2] => Array
(
[host] => remote2.easydns.com
[type] => A
[ip] => 212.100.224.80
[class] => IN
[ttl] => 81241
)
[3] => Array
(
[host] => ns1.easydns.com
[type] => A
[ip] => 216.220.40.243
[class] => IN
[ttl] => 81241
)
[4] => Array
(
[host] => ns2.easydns.com
[type] => A
[ip] => 216.220.40.244
[class] => IN
[ttl] => 81241
)
)
NOTES
Note
For compatibility with versions before PHP 5.3.0 on some operating systems, try the PEAR class Net_DNS.
SEE ALSO
dns_get_mx(3), dns_check_record(3).
PHP Documentation Group DNS_GET_RECORD(3)