444 No Response

An nginx configuration value, not a response: return 444 makes nginx close the connection without sending anything.

Unofficial code. 444 is used only by nginx. It is not in the IANA registry or any HTTP standard, and other software may give the number a different meaning or none.

Code: 444
Reason phrase: No Response
Class: 4xx Client error
Used by: nginx
Cacheable by default: No

What it means

Client error: the problem lies with the request. Repeating it unchanged will normally fail again.

Usual causes. Server blocks that drop unwanted requests, such as bots or requests for an unknown host name.

What to do. Clients see a closed connection (for example ERR_EMPTY_RESPONSE), never a 444. The number appears only in nginx's own access log.

How clients and crawlers treat it

Google Search. Googlebot never receives this code: for a 444 it sees a dropped connection, which Google treats like a network error and a reason to slow down crawling; a 499 is only a line in the server's log. Source: Google Search Central, How HTTP status codes, and network and DNS errors affect Google Search.

Caching. Not cacheable by default (RFC 9110 section 15.1 does not list it). A cache stores it only when the response says so with Cache-Control or Expires.

Example response

HTTP/1.1 444 No Response
Content-Type: text/plain; charset=utf-8

No Response

How to send 444

nginx

location /wp-login.php {
    return 444;   # close the connection, send nothing
}

Related codes

All status codes · All 4xx codes

Names and numbers from the IANA HTTP Status Code Registry (this code is not in it). Google Search behaviour as documented by Google Search Central.