Php find domain controller

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In PHP, how do I do an LDAP query to find all Domain Controllers?
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More answer with same ag
gethostbyname
Примеры
Смотрите также
User Contributed Notes 30 notes

In PHP, how do I do an LDAP query to find all Domain Controllers?

The Domain Controllers OU isn’t in the Users OU (unless you’ve reorganized your AD setup). You need to modify your LDAP query to use a base DN of just DC=our_domain,DC=com .

gethostbyname

Возвращает адрес IPv4 или строку, содержащую неизмененный hostname в случае возникновения ошибки.

Примеры

Пример #1 Простой пример использования gethostbyname()

$ip = gethostbyname ( ‘www.example.com’ );

Смотрите также

gethostbyaddr() — Получает доменное имя хоста, соответствующее переданному IP-адресу
gethostbynamel() — Получает список IPv4-адресов, соответствующих переданному доменному имени хоста
inet_pton() — Конвертирует читаемый IP-адрес в его упакованное представление in_addr
inet_ntop() — Конвертирует упакованный интернет-адрес в читаемый формат

User Contributed Notes 30 notes

If you do a gethostbyname() and there is no trailing dot after a domainname that does not resolve, this domainname will ultimately be appended to the server-FQDN by nslookup.

So if you do a lookup for nonexistentdomainname.be your server may return the ip for nonexistentdomainname.be.yourhostname.com, which is the server-ip.

To avoid this behaviour, just add a trailing dot to the domainname; i.e. gethostbyname(‘nonexistentdomainname.be.’)

This function says «Returns the IPv4 address or a string containing the unmodified hostname on failure.

This isn’t entirely true, any hostname with a null byte in it will only return the characters BEFORE the null byte.

$hostname = «foo\0bar» ;
var_dump ( $hostname );
var_dump ( gethostbyname ( $hostname ));
?>

Results:
string ‘foo�bar’ (length=7)
string ‘foo’ (length=3)

Important note: You should avoid its use in production.

DNS Resolution may take from 0.5 to 4 seconds, and during this time your script is NOT being executed.

Your customers may think that the server is slow, but actually it is just waiting for the DNS resolution response.

You can use it, but if you want performance, you should avoid it, or schedule it to some CRON script.

Options for the underlying resolver functions can be supplied by using the RES_OPTIONS environmental variable. (at least under Linux, see man resolv.conf)

Set timeout and retries to 1 to have a maximum execution time of 1 second for the DNS lookup:
putenv ( ‘RES_OPTIONS=retrans:1 retry:1 timeout:1 attempts:1’ );
gethostbyname ( $something );
?>

You should also use fully qualified domain names ending in a dot. This prevents the resolver from walking though all search domains and retrying the domain with the search domain appended.

For doing basic RBL (Real Time Blacklist) lookups with this function do:

$host = ‘64.53.200.156’ ;
$rbl = ‘sbl-xbl.spamhaus.org’ ;
// valid query format is: 156.200.53.64.sbl-xbl.spamhaus.org
$rev = array_reverse ( explode ( ‘.’ , $host ));
$lookup = implode ( ‘.’ , $rev ) . ‘.’ . $rbl ;
if ( $lookup != gethostbyname ( $lookup )) echo «ip: $host is listed in $rbl \n» ;
> else echo «ip: $host NOT listed in $rbl \n» ;
>
?>

Tomas V.V.Cox

gethostbyname and gethostbynamel does not ask for AAAA records. I have written two functions to implement this. gethostbyname6 and gethostbynamel6. I don’t believe this issue has been addressed yet.

They are made to replace gethostbyname[l], in a way that if $try_a is true, if it fails to get AAAA records it will fall back on trying to get A records.

Feel free to correct any errors, I realise that it is asking for *both* A and AAAA records, so this means two DNS calls.. probably would be more efficient if it checked $try_a before making the query, but this works for me so I’ll leave that up to someone else to implement in their own work.. the tip is out there now anyway..

function gethostbyname6($host, $try_a = false) // get AAAA record for $host
// if $try_a is true, if AAAA fails, it tries for A
// the first match found is returned
// otherwise returns false

function gethostbynamel6($host, $try_a = false) // get AAAA records for $host,
// if $try_a is true, if AAAA fails, it tries for A
// results are returned in an array of ips found matching type
// otherwise returns false

$dns6 = dns_get_record($host, DNS_AAAA);
if ($try_a == true) $dns4 = dns_get_record($host, DNS_A);
$dns = array_merge($dns4, $dns6);
>
else < $dns = $dns6; >
$ip6 = array();
$ip4 = array();
foreach ($dns as $record) if ($record[«type»] == «A») $ip4[] = $record[«ip»];
>
if ($record[«type»] == «AAAA») $ip6[] = $record[«ipv6»];
>
>
if (count($ip6) < 1) if ($try_a == true) if (count($ip4) < 1) return false;
>
else return $ip4;
>
>
else return false;
>
>
else return $ip6;
>
>

On a side-note, PHP (5.0.4, but probably other versions too) can cache gethostbyname information.

In short, once PHP looks up an address, it may not actually perform another lookup as you may expect. In my particular case (I think) the problem was a change to resolv.conf didn’t take effect inside PHP (although nslookup/ping etc worked fine). Stop/Starting Apache fixed it (although a simple ‘restart’ (kill -HUP) didn’t).

In short, if you change resolv.conf, stop and restart Apache.

When using gethostbynamel() and gethostbyname() together, you must do gethostbynamel() first, otherwise it will always give you one IP (or none) from the cache, and not return the full lookup.

In PHP4 you can use gethostbyname() but I have found this unreliable when doing lookups on entries that return A records on the private network. PHP5 has a much better routine — dns_get_record(). If you are stuck with PHP4 or don’t want to upgrade you can use dig:

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