HTTP Status Codes

451 Unavailable For Legal Reasons

The resource is blocked for legal reasons — a court order, government censorship, or a takedown demand. The number nods to Fahrenheit 451.

What it means

451 Unavailable For Legal Reasons (RFC 7725) signals that access is denied due to a legal requirement rather than a technical one. The response should ideally explain who imposed the restriction, promoting transparency about censorship and takedowns.

Why it matters

  • It distinguishes legally-mandated blocking from ordinary 403s and supports censorship transparency.

Common mistakes

  • Using 403 for legally-blocked content, hiding the legal nature of the restriction.

How WebInspect checks this

  • WebInspect reports the status and any explanatory headers or Link relations for legal blocks.