Jan 23, 2020 08:00:00

Why was one day suddenly blocked by a large number of websites?

Content delivery networks (CDNs) , which cache original web content and distribute load by distributing web content from cache servers located around the world, are widely used in business and academic fields. One of those CDNs, Cloudflare, was suddenly blocked one day and lost his website, Jan Harasym reported on his blog.

Cloudflare is turning off the internet for me
https://blog.dijit.sh/cloudflare-is-turning-off-the-internet-for-me

One day, Jan came to the office, opened a web browser on his laptop and updated the page, and most of the tabs that were open displayed 'Sorry, you are blocked'. After reading the notice, it seems that Jan's action was determined to be an attack on the website and was blocked by Cloudflare. The website owner is being asked to contact us, but it is difficult because the website cannot be accessed.

Jan speculated that disabling Javascript might be the cause, but the display did not disappear even after several hours with Javascript enabled.

So Jan turned to

Hackers News for a solution.

Cloudflare is turning off the internet for me | Hacker News
https://news.ycombinator.com/item?id=22109969

While waiting for the answer to the question, Jan tries and tries to access the page. When I tried to access it using Chrome, which I do not usually use, the page was displayed. Access from your usual browser is still blocked.

Looking at the comment posted on Hacker News `` Is it due to the browser's user agent '', Jan remembered that he had rewritten the user agent before, and changed the user agent of his usual browser to Chrome. I decided to rewrite the default settings. Then the page was displayed without being blocked.

It is said that malicious bots are often left old without user agents being updated since they were created. It has been pointed out that Jan's user agent was set by himself and was a bit older than Firefox 2017, so it was considered a malicious bot.