checkdnsrr
(PHP 4, PHP 5)
checkdnsrr — Check DNS records corresponding to a given Internet host name or IP address
Description
bool checkdnsrr
( string
$host
[, string $type = "MX"
] )
Searches DNS for records of type type
corresponding to host.
Parameters
-
host -
hostmay either be the IP address in dotted-quad notation or the host name. -
type -
typemay be any one of: A, MX, NS, SOA, PTR, CNAME, AAAA, A6, SRV, NAPTR, TXT or ANY.
Return Values
Returns TRUE if any records are found; returns FALSE if no records
were found or if an error occurred.
Changelog
| Version | Description |
|---|---|
| 5.3.0 | This function is now available on Windows platforms. |
| 5.2.4 |
TXT type was added.
|
| 5.0.0 |
AAAA type was added.
|
Notes
Note:
For compatibility with Windows before this was implemented, then try the » PEAR class » Net_DNS.
See Also
- dns_get_record() - Fetch DNS Resource Records associated with a hostname
- getmxrr() - Get MX records corresponding to a given Internet host name
- gethostbyaddr() - Get the Internet host name corresponding to a given IP address
- gethostbyname() - Get the IPv4 address corresponding to a given Internet host name
- gethostbynamel() - Get a list of IPv4 addresses corresponding to a given Internet host name
- the named(8) manual page
- checkdnsrr
- closelog
- define_syslog_variables
- dns_check_record
- dns_get_mx
- dns_get_record
- fsockopen
- gethostbyaddr
- gethostbyname
- gethostbynamel
- gethostname
- getmxrr
- getprotobyname
- getprotobynumber
- getservbyname
- getservbyport
- header_register_callback
- header_remove
- header
- headers_list
- headers_sent
- http_response_code
- inet_ntop
- inet_pton
- ip2long
- long2ip
- openlog
- pfsockopen
- setcookie
- setrawcookie
- socket_get_status
- socket_set_blocking
- socket_set_timeout
- syslog
Коментарии
criffoh at gmail dot com is right. Before you check domain, you must convert to ascii with idn_to_ascii function:
http://us2.php.net/manual/en/function.idn-to-ascii.php .
var_dump(checkdnsrr('ñandu.cl', 'A')); // returns false
var_dump(checkdnsrr(idn_to_ascii('ñandu.cl'), 'A')); // return true
Important Warning:
You need to add a dot to the end of the host name to make a fully qualified domain name.
To see why, try executing the following pieces of code:
$d1="gmail.con";
$d2="gmail.con.";
$r1=checkdnsrr($d1, "MX");
$r2=checkdnsrr($d2, "MX");
var_dump($r1);
var_dump($r2);
You will see that without the dot it claims that the domain "gmail.con" is valid.
Note that if you time the "checkdnsrr()" calls you will also see it takes longer without the dot because it treats it as a relative domain and does several tries based on the host name it is running on.
NB: in case you're interested, being treated as a relative domain explains what is happening. If your host is "example.com" the relative domain will eventually resolve to "gmail.con.com." which can be looked up, hence it wrongly claims "gmail.con" exists
I always think you should state the blindingly obvious.A function that contains checkdnsrr will return false without an internet connection.
So in a production environment you need an active internet connection to return a true result with a valid email address.