Databay field notes
Proxy guides, experiments & operator notes
Engineering guides and first-party measurements for people operating proxy-backed data systems.
All articles
70 entries
ERR_CONNECTION_REFUSED: What It Means and How to Fix It
ERR_CONNECTION_REFUSED means the server answered no, instantly. What refusal tells you, the localhost case, and ranked fixes for each side.
10 min readRead

ERR_CONNECTION_RESET: What It Means and How to Fix It
ERR_CONNECTION_RESET means the connection opened and was then killed by a TCP reset. How to tell who sent it, and the fix that follows.
12 min readRead

ERR_CONNECTION_TIMED_OUT: What It Is and How to Fix It
ERR_CONNECTION_TIMED_OUT means pure silence before the browser gave up. How silence differs from refusal and the fixes that match each...
10 min readRead

ERR_NAME_NOT_RESOLVED: What It Means and How to Fix It
ERR_NAME_NOT_RESOLVED means DNS returned no address, so your browser never connected. Two commands that localize it, then the fixes that...
12 min readRead

ERR_TOO_MANY_REDIRECTS: How to Break a Redirect Loop
The browser gave up on a redirect loop. Fix it as a visitor in two minutes, see the loop with curl, and repair the server rules causing it.
10 min readRead

ERR_TUNNEL_CONNECTION_FAILED: Causes and How to Fix It
ERR_TUNNEL_CONNECTION_FAILED means a proxy would not open the CONNECT tunnel HTTPS needs. What a tunnel is, and fixes ranked by the real...
12 min readRead

Error 1015: You Are Being Rate Limited (How to Fix It)
Error 1015 is Cloudflare enforcing a site's rate limit at the edge. Why you tripped it, how long it lasts, and fixes for visitors and...
10 min readRead

Error 1020 Access Denied: Causes and How to Fix It
Error 1020 means a site's own firewall rule refused your request at the edge. Why you matched it, and the one thing that actually...
12 min readRead

Error 522: Connection Timed Out and Whose Fault It Is
Error 522 means a CDN edge could not get a usable connection to the site's origin. Why it is almost never the visitor's fault, and the...
12 min readRead

What Is Msftconnecttest.com and Why Does It Redirect?
Msftconnecttest.com is how Windows checks for internet access. Why it is not malware, why the redirect tab opens, and the fixes that work.
12 min readRead

What Is Doubleclick.net? Google's Ad and Tracking Domain
Doubleclick.net is Google's ad serving and measurement domain. Why it loads on sites you visit, whether it is malware, and what limiting...
12 min readRead

What Is Gstatic.com? Google's Static Content Domain
Gstatic.com is Google's cookieless domain for static files like fonts and scripts. What it does, why devices ping it, and what breaks if...
10 min readRead
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