How to block IAS crawler
Operated by Integral Ad Science. Integral Ad Science (IAS) is the global market leader in digital ad verification, offering technologies that drive high-quality advertising media.
How it identifies itself
IAS crawler (ias_crawler; http://integralads.com/site-indexing-policy/)
robots.txt
What the agent asks to be told. It obeys this or it does not — nothing enforces it.
User-agent: IAS Disallow: /
nginx
In the server block, then reload.
# In the server block. 403 rather than 444: a closed connection tells the
# operator nothing, and an agent that gets a status code can log it.
if ($http_user_agent ~* "(ias_crawler|IAS Crawler (ias_crawler; http:|Ias Crawler)") {
return 403;
}
Apache
In .htaccess or the vhost.
BrowserMatchNoCase "ias_crawler" bad_bot
BrowserMatchNoCase "IAS Crawler" bad_bot
BrowserMatchNoCase "Ias Crawler" bad_bot
<RequireAll>
Require all granted
Require not env bad_bot
</RequireAll>
Cloudflare
Security → WAF → Custom rules.
# Security → WAF → Custom rules, action: Block (http.user_agent contains "ias_crawler") or (http.user_agent contains "IAS Crawler") or (http.user_agent contains "Ias Crawler")
WordPress
A child theme's functions.php, or a small plugin.
// functions.php of a child theme, or a small plugin. Runs before WordPress
// builds the page, so a blocked agent costs one PHP process and no queries.
add_action('init', function () {
$agent = $_SERVER['HTTP_USER_AGENT'] ?? '';
foreach (['ias_crawler', 'IAS Crawler', 'Ias Crawler'] as $needle) {
if (stripos($agent, $needle) !== false) {
status_header(403);
exit('Blocked: IAS crawler');
}
}
});
robots.txt is a request. The rules below it are the wall.
IAS crawler publishes a token, so the directive above will work for as long as it keeps honouring it — and nothing except its own good manners makes it. The server rules match on a header the requester sets, which stops the agent that says who it is and not the one that copies somebody else's name. Botscope verifies identity against DNS and published address ranges, records which check decided each request, and shows you the ones that lied.