Introduction

Since a few months ago, I have been experiencing random "connection refused" issues with Google Chrome. Sometimes certain web pages just won't load, but they work fine on other devices. Although it seemed strange, I thought it might be a server configuration issue and didn't cause much trouble, so I continued using it.

Setting up a custom domain

Later on, something strange happened when I casually bought a .dev domain. After setting up the CNAME and ensuring that SSL was working, no matter how many times I refreshed in Chrome, it kept showing "CONNECTION_REFUSED". Typically, there are a few reasons for this issue. The first possibility is that the server hasn't opened the port, and the other is firewall settings. I checked both of these settings and found no issues. Just to be safe, I used dig xxx.dev +nostats +nocomments +nocmd to verify if the CNAME was set correctly. Everything was fine.

Next, I checked the SSL issue. I used SSL checker to confirm if SSL was configured correctly, and it was.

Alright, maybe it takes some time for the settings to take effect, so I waited for 10 minutes and checked again. Still no luck, Chrome still showed the dreaded "CONNECTION_REFUSED". Then I tried accessing the website on my phone and found that it worked successfully.

At this point, I started to suspect that there might be some misconfiguration on my computer. So, I began checking the relevant settings. First, I used curl blog.kalan.dev to see what would happen. The result showed an error:

curl: (7) Failed to connect to blog.kalan.dev port 80: Connection refused

Hmm, the result from Chrome and curl was the same, which made me even more certain that there was an issue with the computer's settings. Next, I used wget to see what was going on.

wget https://blog.kalan.dev
--2019-03-18 23:11:46--  https://blog.kalan.dev/
Resolving blog.kalan.dev (blog.kalan.dev)... 127.0.0.1, 0.0.0.1
Connecting to blog.kalan.dev (blog.kalan.dev)|127.0.0.1|:443... failed: Connection refused.
Connecting to blog.kalan.dev (blog.kalan.dev)|0.0.0.1|:443... failed: No route to host.

Wait a minute, it resolved to 127.0.0.1? Does that mean I added this domain to the hosts file on my machine? I had no recollection of doing that, but with a glimmer of hope, I checked the /etc/hosts and /private/etc/hosts files.

The result was still the same. I hadn't set the domain in the local hosts file. But at least I knew the reason now. Somehow, some configuration caused blog.kalan.dev to be set to 127.0.0.1. At this point, I had no idea what could have caused it. But as I was randomly trying things, I noticed something strange. I found that any xxx.dev domain had the same issue, while other domains didn't.

Suddenly, I remembered something. About 4 years ago, I downloaded powder to learn Ruby On Rails. Essentially, it allows you to access websites and automatically starts the server for you. It's super convenient! So, I happily installed it back then.

However, upon closer inspection of the official documentation, I found that section 3.1 stated:

The POW_DOMAINS environment variable specifies a comma-separated list of top-level domains for which Pow will serve DNS queries and HTTP requests. The default value for this list are the two test,dev domains, meaning Pow will configure your system to resolve *.test and *.dev to 127.0.0.1 and serve apps in ~/.pow under the .test and .dev domains.

Oh, so that's why it hijacked my IP and pointed it to 127.0.0.1, and since my computer didn't have port 443 open, that's why I was getting "CONNECTION_REFUSED". So, those web pages I couldn't see were probably all using the .dev domain.

A few things to note:

• When encountering "CONNECTION_REFUSED", use wget to check if the host connection is correct.
• Alternatively, use curl --ipv4 -v "your.site.com" to check the host connection.