DN42 is an experimental network, where everyone helps everyone. Nobody is going to blame you if you screwed up. You may seek help at DN42's IRC channel, mailing list or the unofficial Telegram group.Since DN42 is a network for experimentation, a lot of relatively inexperienced users also participate in it. Therefore, occasionally an inexperienced user may misconfigure his/her system and impact the whole DN42 network or even shut it down.As a more experienced user, here I will teach new users about some operations that can kill the network and about defense against such misconfigurations that everyone can set up against peers.WARNING: You should not actually perform these operations in DN42. You should focus more on protecting yourself against them....

Some parts of the content come from https://hostedtalk.net/t/connecting-uptime-robot-with-ns1-dns-api/3883。GoalI have quite a few VPSes around the world, but my website had been served by a single VPS in Los Angeles for a long time. Because I purchase VPSes from small providers for their specific routing configuration or low price, the network of this VPS can be unstable from time to time. Although it's rare, I had to manually point the DNS to another VPS in case of an outage and switch back after it's back up. Therefore, I want to serve my website with all my VPSes, and automatically reroute traffic to other VPSes if one VPS is down.Synchronizing website data is of no difficulty since I use Hexo, a static site generator....

List of NixOS Series Posts:NixOS Series 1: Why I fell in loveNixOS Series 2: Basic Config, Nix Flake & Batch DeployRecommended: NixOS & Nix Flakes - A Guide for Beginners by Ryan YinNixOS Series 3: Software Packaging 101NixOS Series 4: "Stateless" Operating SystemThis is the second post in my NixOS series and mainly focuses on:Basic format of NixOS config files and how to edit themFlake functionality of Nix package managerDeploy-RS deployment toolThis post assumes that you've installed NixOS with NixOS's official installation manual.Changelog2023-05-10: Add a recommended post: NixOS & Nix Flakes - A Guide for Beginners by Ryan Yin.2021-12-18: NixOS 21.11 still doesn't come with Flake functionality by default. Relevant information is updated....

List of NixOS Series Posts:NixOS Series 1: Why I fell in loveNixOS Series 2: Basic Config, Nix Flake & Batch DeployRecommended: NixOS & Nix Flakes - A Guide for Beginners by Ryan YinNixOS Series 3: Software Packaging 101NixOS Series 4: "Stateless" Operating SystemRight now, I'm gradually migrating my servers from Devuan Linux to NixOS. NixOS is a Linux distribution centered on a set of Nix configuration files located in /etc/nixos, which is used to install and configure the whole operating system. Because this configuration set defines ALL config files and packages on the system, as long as you use the same config files, you will absolutely get the same operating system every time you reinstall. Nix configuration language is also Turing complete,...

Jenkins is a free and open-source CI/CD software widely used in all kinds of scenarios. The main advantage of Jenkins is its grand collection of plugins capable of all sorts of jobs, including deploying with SCP or Ansible, analyzing code with Cppcheck, and notifying job status with Telegram or DingTalk.Previously I also used Jenkins for automation of numerous jobs, like rebuilding my Docker images, deploying the blog you're visiting right now, and even auto sign-in to Genshin Impact.But Jenkins is a CI with a long history, and its predecessor Hudson was released back in 2005. Therefore, Jenkins executes commands directly when it comes to running jobs instead of using modern approaches such as containers....

After I set up a DN42 WHOIS server with Nginx, I configured my DN42 Looking Glass to use this service. As my Looking Glass is capable of running as a Telegram bot, fellow group members are looking up WHOIS information of IPs and domains with it.But soon we noticed a problem. A significant part of members have applied for ASNs and IP ranges on the public Internet after they're familiar enough with DN42, and they're peering at Internet Exchange Points. Therefore, they often need to lookup some public Internet IPs, ASNs, and domains, yet none of the Telegram bots in our group can do so. It would be quite helpful for us if there exists a WHOIS server that proxies lookups to relevant registries.Proxying is exactly what Nginx is good at. With some modifications to Nginx,...

DN42, aka Decentralized Network 42, is a large, decentralized VPN-based network. But unlike other traditional VPNs, DN42 itself doesn't provide any VPN exits, which means it doesn't allow you to bypass Internet censorships or unlock streaming services. On the contrary, the goal of DN42 is to simulate another Internet. It uses much of the technology running on modern Internet backbones (BGP, recursive DNS, etc), and is a great replica of a real network environment.In short, DN42 is:NOT suitable for users only seeking privacy protection or bypassing censorshipNOT suitable for users consuming large amounts of bandwidth/data, such as for unlocking streaming servicesIS suitable for users learning about networking, practicing configuration of servers and routers,...

In my previous post, "Setting up Gopher Site with Nginx", I mentioned that the Gopher service is a byproduct of my original plan: modifying Nginx into a WHOIS server for DN42. This post will explore into details of that process.The WHOIS ProtocolFirst, we can find a WHOIS server to observe its response. Choose the WHOIS server for .pub domain as an example, and run telnet whois.nic.pub 43:# Type following line and hit enterlantian.pub# WHOIS server responded with:Domain Name: lantian.pubRegistry Domain ID: c69e5ccf9d834900be26f88fddc5c9e4-DONUTSRegistrar WHOIS Server: whois.dnspod.cnRegistrar URL: https://www.dnspod.cnUpdated Date: 2021-01-07T14:09:11ZCreation Date: 2016-10-23T08:36:41ZRegistry Expiry Date: 2029-10-23T08:36:41ZRegistrar: DNSPod, Inc....

Changelog2021-03-24: Improve post-processing, add scripts for parsing links and images.2021-03-21: Initial version.What's GopherGopher is a protocol born in the early ages of the Internet. It was invented at the University of Minnesota in 1991, with a purpose similar to HTTP today. The protocol itself is extremely simple:Client connects to TCP port 70 of the server, and send one line of URL ending with CRLF, e.g. some_dir/hello.txtServer sends data of the requested file and closes the connection.And we're done.The server could be returning a text file, a picture, a binary file, or a Gopher list file called Gophermap with special formatting. Each line of the file is composed of the following fields:A character representing the type of this line, may it be text (i), a link to a text file (0)...

In my network configuration, some of my Docker containers, for example DNS, need to achieve high availability with Anycast. In my previous post, I created a Busybox container and run tail -f /dev/null, in order to let it persist infinitely, but without using any CPU cycles, to maintain a network namespace used by both the server application and BIRD.In short: I invented a Pod in Kubernetes on my own.I don't use K8S, since my nodes run individually rather than in a cluster, I don't need the cluster functionality of K8S at all. In addition, K8S is difficult to set up.But on another thought, a Busybox container seems like an overkill for this purpose, and I have to set the entrypoint manually. It would be great if I have a tiny Docker image that only sleeps indefinitely.Plan A:...