gethostbynamel
(PHP 4, PHP 5)
gethostbynamel — Get a list of IPv4 addresses corresponding to a given Internet host name
说明
$hostname
)
Returns a list of IPv4 addresses to which the Internet host
specified by hostname resolves.
参数
-
hostname -
The host name.
返回值
Returns an array of IPv4 addresses or FALSE if
hostname could not be resolved.
范例
Example #1 gethostbynamel() example
<?php
$hosts = gethostbynamel ( 'www.example.com' );
print_r ( $hosts );
?> 以上例程会输出：
Array
(
[0] => 192.0.34.166
)
参见
- gethostbyname() - Get the IPv4 address corresponding to a given Internet host name
- gethostbyaddr() - 获取指定的IP地址对应的主机名
- checkdnsrr() - 给指定的主机（域名）或者IP地址做DNS通信检查
- getmxrr() - Get MX records corresponding to a given Internet host name
- the named(8) manual page
用户评论:
[#1] info at methfessel-computers.de [2006-09-29 15:27:55]
The solution is simpel. Just add a . (point) to the end of the URL for correct name resolving.
Without this point PHP thinks it's a subdomain of your local domain and so returns the "local-IP".
[#2] webdev at concraption dot com [2005-09-19 11:25:08]
In PHP 5.0.4, gethostbynamel returns an empty string instead of false if the lookup fails. A simple workaround for this error is to use is_array() in an IF block:
<?php
$hosts = gethostbynamel($hostname);
if (is_array($hosts)) {
echo "Host ".$hostname." resolves to:<br><br>";
foreach ($hosts as $ip) {
echo "IP: ".$ip."<br>";
}
} else {
echo "Host ".$hostname." is not tied to any IP.";
}
?>
[#3] Skyld at o2 dot co dot uk [2004-09-25 01:45:12]
Obviously, in some cases, not all IPs are likely to be useful while checking a hostname. Sometimes also, not all IPs will work. This code will check for the first WORKING IP from the list. Or at least it should - I haven't had time to test it yet.
Needs domain parameter, and port and max IPs to check are optional.
If port is not set, it will check HTTP port 80, and if max IPs to check is not set, it will only check the first 10 IPs from the list.
Hope it helps someone.
<?php
function checkhostlist($domain, $port = 80, $maxipstocheck = 10) {
? $hosts = gethostbynamel($domain);
for ($chk=0;$chk<$maxipstocheck;$chk++) {
if (isset($hosts[$chk])) {
$th = fsockopen($domain, $port);
if ($th) {
fclose($th);
return $hosts[$chk];
break;
}
}
}
}
?>