Save Tinyboard docs (2012-10-16) from web.archive.org

docs/config/dnsbl.md

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+DNS Blacklists (DNSBL)
+======================
+
+To further prevent spam and abuse, you can use DNS blacklists (DNSBL). A DNSBL is a list of IP addresses published through the Internet Domain Name Service (DNS) either as a zone file that can be used by DNS server software, or as a live DNS zone that can be queried in real-time.
+
+By default, Tinyboard checks all addresses against just one blacklist:
+```
+tor.dnsbl.sectoor.de
+```
+This prevents Tor exit nodes from making posts and is recommended as a large majority of abuse comes from Tor because of the strong anonymity associated with it.
+
+You can add more blacklists by [putting them in your configuration](../config.md). You should refer to the blacklist’s documentation to figure out which responses you wish to block.
+```php
+// Block "127.0.0.2" responses from this blacklist.
+$config['dnsbl'][] = array('bl.spamcannibal.org', 2);
+
+// This does exactly the same thing as above:
+// $config['dnsbl'][] = array('bl.spamcannibal.org', array(2));
+// $config['dnsbl'][] = array('bl.spamcannibal.org', '127.0.0.2');
+
+// Block "127.0.0.8" and "127.0.0.9" responses from this blacklist.
+$config['disbl'][] = array('dnsbl.dronebl.org', array(8, 9));
+
+// Determine whether or not to block listed users with an anonymous function (PHP 5.3.0+)
+// This is especially relevant if you plan to use Http:BL.
+$config['dnsbl'][] = array('<your access key>.%.dnsbl.httpbl.org', function($ip) {
+	$octets = explode('.', $ip);
+
+	// days since last activity
+	if ($octets[1] > 14)
+		return false;
+
+	// "threat score" (http://www.projecthoneypot.org/threat_info.php)
+	if ($octets[2] < 5)
+		return false;
+
+	return true;
+}, 'dnsbl.httpbl.org'); // hide our access key
+
+
+// Just block anything listed in here (ie. not NXDOMAIN)
+$config['dnsbl'][] = 'another.blacklist.net';
+```
+See [here](https://web.archive.org/web/20121003095945/http://www.dnsbl.info/dnsbl-list.php) for a larger list of blacklists.
+
+This syntax for configuring DNSBL servers was stolen (with permission) from [Frank Usrs](https://web.archive.org/web/20121003095945/mailto:frankusrs@gmail.com).
+
+Exceptions
+----------
+To combat false positives, administrators can add “exceptions” to these lists, meaning that certain IP addresses will skip the DNSBL check entirely.
+```php
+$config['dnsbl_exceptions'][] = '8.8.8.8';
+$config['dnsbl_exceptions'][] = '55.55.55.55';
+```