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    Categories: SEO

New HTTP Status Code 451 for Legal Takedowns

For the first time in a while, we have a brand new status code. The new status code is meant to serve as a status code to show when a page or site has been taken offline for legal reasons.

The new status code is 451 with the description set as “Unavailable for Legal Reasons” on the page.

They do request that ISPs who are using this status code also include details about why it has been removed, although I can see it being used often without the explanation.

Responses using this status code SHOULD include an explanation, in the response body, of the details of the legal demand: the party making it, the applicable legislation or regulation, and what classes of person and resource it applies to. For example:

HTTP/1.1 451 Unavailable For Legal Reasons
Link: <https://spqr.example.org/legislatione>; rel=”blocked-by”
Content-Type: text/html

<html>
<head><title>Unavailable For Legal Reasons</title></head>
<body>
<h1>Unavailable For Legal Reasons</h1>
<p>This request may not be serviced in the Roman Province
of Judea due to the Lex Julia Majestatis, which disallows
access to resources hosted on servers deemed to be
operated by the People’s Front of Judea.</p>
</body>
</html>

In a blog post by Mark Nottingham he says that it became apparent that there would be benefits from adding a new status code, even with the concern that they are limited to the 400-499 range, and once they are gone, they have no more in the 4xx range.  But he felt it was more important as censorship issues become more prevalent as well as sites wanting the ability to crawl and discover pages that have been removed via legal takedowns and displaying a specific status code that represents that.

More importantly, we started to hear from members of the community that they wanted to be able to discover instances of censorship in an automated fashion. For example, Lumen (previously, Chilling Effects) and Article19 expressed interest in being able to spider the Web to look for the 451 status code, so they could catalogue censorship.

He also mentions that some sites have begun to adopt the 451 status code experimentally.

They interestingly make a case where a party might not want a case of a page being taken offline as a result of legal action.

5. Security Considerations

Clients cannot rely upon the use of the 451 status code. It is
possible that certain legal authorities might wish to avoid
transparency, and not only demand the restriction of access to
certain resources, but also avoid disclosing that the demand was
made.

So it is possible if the use of 451 becomes standard, that some legal takedowns might request that a 451 status code not be used, specifically because some might deem it too transparent.

Previously, companies were usually using the 403 Forbidden status code, although it didn’t exactly fit a scenario where a site or page was removed for legal reasons.

H/T Eric Wu

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Jennifer Slegg

Founder & Editor at The SEM Post
Jennifer Slegg is a longtime speaker and expert in search engine marketing, working in the industry for almost 20 years. When she isn't sitting at her desk writing and working, she can be found grabbing a latte at her local Starbucks or planning her next trip to Disneyland. She regularly speaks at Pubcon, SMX, State of Search, Brighton SEO and more, and has been presenting at conferences for over a decade.
Jennifer Slegg :Jennifer Slegg is a longtime speaker and expert in search engine marketing, working in the industry for almost 20 years. When she isn't sitting at her desk writing and working, she can be found grabbing a latte at her local Starbucks or planning her next trip to Disneyland. She regularly speaks at Pubcon, SMX, State of Search, Brighton SEO and more, and has been presenting at conferences for over a decade.