CensysInspect User Agent: What It Is & How to Block It

01 · Operator

Who operates CensysInspect

Company: Censys
Type: Monitoring bot
Official docs: docs.censys.com

02 · Behavior

What CensysInspect does

Censys scans IP addresses and records the services they expose. The results appear in Censys Search and support vulnerability research. Censys publishes the subnets and ASNs it scans from.

03 · Impact

Why CensysInspect matters for your site

If you allow it

Helps security researchers find exposed and vulnerable services
Uses documented IP ranges and ASNs

If you block it

No traffic or visibility benefit
Your exposed services become searchable in Censys

04 · Allow

How to allow CensysInspect

robots.txt

User-agent: CensysInspect
Allow: /

Cloudflare

# Security › WAF › Custom rules › Create rule
Expression: (http.user_agent contains "CensysInspect")
Action:     Skip › All Super Bot Fight Mode rules

# Also check Security › Bots: "Block AI bots" can block it regardless of robots.txt.

WordPress

# WordPress serves a virtual robots.txt. Edit it with your SEO plugin:
# Yoast: SEO › Tools › File editor · Rank Math: General Settings › Edit robots.txt
User-agent: CensysInspect
Allow: /

nginx

# nginx serves every user agent by default.
# Make sure no rule like this blocks it:
# if ($http_user_agent ~* "CensysInspect") { return 403; }

Apache

# Apache serves every user agent by default.
# Make sure .htaccess has no rule like this:
# RewriteCond %{HTTP_USER_AGENT} CensysInspect [NC]
# RewriteRule .* - [F,L]

05 · Block

How to block CensysInspect

Start with robots.txt. If CensysInspect keeps showing up in your logs, block it at your CDN or web server.

robots.txt

User-agent: CensysInspect
Disallow: /

Cloudflare

# Security › WAF › Custom rules › Create rule
Expression: (http.user_agent contains "CensysInspect")
Action:     Block

WordPress

# WordPress serves a virtual robots.txt. Edit it with your SEO plugin:
# Yoast: SEO › Tools › File editor · Rank Math: General Settings › Edit robots.txt
User-agent: CensysInspect
Disallow: /

nginx

# In your server { } block:
if ($http_user_agent ~* "CensysInspect") {
    return 403;
}

Apache

# .htaccess
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTP_USER_AGENT} CensysInspect [NC]
RewriteRule .* - [F,L]
</IfModule>

06 · User agents

User agents we see for CensysInspect

The user agent published by the operator:

Mozilla/5.0 (compatible; CensysInspect/1.1; +https://about.censys.io/)

07 · Verification

Is it really CensysInspect?

CensysInspect’s operator publishes no IP ranges or hostnames, so requests cannot be verified. Treat the user agent as a claim, and watch your logs for unusual request rates.

FAQ

Questions about CensysInspect

How do I opt out of Censys scanning?

Censys recommends dropping traffic from its published subnets and ASNs at your firewall. You can also block the CensysInspect user agent.

Which networks does Censys scan from?

Censys lists its IPv4 and IPv6 subnets on its opt-out page. It names AS398722, AS398705 and AS398324 as its ASNs.

Is CensysInspect traffic an attack?

Censys states it only scans to collect information for research and security purposes.

CensysInspect is Censys’ monitoring bot