13 posts
The other day someone asked me how I integrate Cloudflare and why it's relatively fast — and why the resolved IPs are still three A records? Let me share my site's architecture and how I use Cloudflare.
It's not just the ICP filing that got revoked — checking cnBeta.com's WHOIS, the domain has been placed under clientHold, halting resolution worldwide. A shutdown like this doesn't come from a small mistake: with the domain itself set to clientHold, they clearly crossed a red line.
Every developer's program differs: some handle JSON well, some XML, some plain TXT. So why not just respond in the format you need? ip.renfei.net now returns different formats based on the Accept request header.
I bought a small industrial PC and started playing with soft routers. Here's my write-up so the next person can skip the pitfalls I hit. This post covers building OpenWRT (LEDE) yourself; follow-ups will cover automating the build with GitHub Actions Workflows and installing the x86 soft router system.
This "ip.renfei.net" upgrade supports not only IPv4 networks but also IPv6 networks, so the JSON you get may be an IPv4 or an IPv6 address. Developers, please update your programs to recognize it. If you only want to query an IPv4 address, use "ipv4.renfei.net", which supports IPv4 only.
You can't directly see the public IP on a computer or server—only the internal IP is visible—so a program cannot know the address of its Internet exit. I wrote another app to obtain the public IP address. It is implemented using serverless function compute, with good availability and speed, so I'm sharing it for everyone to use.
After the computer gets the domain name the user typed in, it queries a server — the DNS server set in our computer. DNS stands for Domain Name System, and every ISP provides a DNS server for users to resolve domain names. This article doesn't cover DNS principles, only the resolution process, so let's go straight to it.
