gethostbynamel
(PHP 4, PHP 5)
gethostbynamel — Get a list of IP addresses corresponding to a given Internet host name
Описание
array gethostbynamel
( string $hostname
)
Returns a list of IP addresses to which the Internet host specified by hostname resolves.
Список параметров
- hostname
-
The host name.
Возвращаемые значения
Returns an array of IP addresses or FALSE if hostname could not be resolved.
Примеры
Пример #1 gethostbynamel() example
<?php
$hosts = gethostbynamel('www.example.com');
print_r($hosts);
?>
Результат выполнения данного примера:
Array ( [0] => 192.0.34.166 )
- 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
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;
}
}
}
}
?>
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:
<?
$hosts = gethostbynamel($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.";
}
?>
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".
If using gethostbyname against the name of the localhost is always giving you 127.0.0.1 but you want the DNS address instead, just put a dot at the end of the name. E.g.,
$foo = gethostbynamel("myhost.example.com");
print_r($foo);
...is giving you this:
Array
(
[0] => 127.0.0.1
)
Then put a dot at the end of the name:
$foo = gethostbynamel("myhost.example.com.");
print_r($foo);
...and now you get something like:
Array
(
[0] => 172.217.1.99
)
不要使用http协议,gethostbynamel函数中