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+---
+title: "Gemini"
+date: 2021-07-01
+tags: ['server']
+short_desc: "A minimalist alternative to HTTP with a modern twist."
+---
+## What is Gemini? {#whatis}
+
+[Gemini](https://gemini.circumlunar.space) is a new
+internet protocol which is different from the HTTP and Gopher. It\'s
+much cleaner and has a growing community and audience of hackers.
+
+### Why use gemini protocol?
+
+-   Gemini capsules (webpages of gemini) are lightweight, minimal, and
+    don\'t use many resources to operate.
+-   It can run along with your websites. Gemini capsules use port 1965
+    by default. Your webserver can run at port 80 or 443 along with
+    gemini server at port 1965.
+-   By exploring an alternative protocol, you can check different ways
+    to serve data and blogs.
+
+To access any gemini urls i.e. `gemini://example.org`, you can use any
+gemini client such as
+[amfora](https://github.com/makeworld-the-better-one/amfora),
+[lagrange](https://gmi.skyjake.fi/lagrange),
+[elpher](https://thelambdalab.xyz/elpher/), etc.
+
+## Instructions
+
+### Create a gemini user
+
+It is most secure and clean to have a separate `gemini` user, so let\'s
+create one:
+
+```sh
+useradd -m -s /bin/bash gemini
+```
+
+Now log in as `gemini` with the following command:
+
+```sh
+su -l gemini
+```
+
+To create and serve a gemini capsule, we need three basic steps:
+
+1.  Content -- the webpages in our capsule
+2.  TLS certificate -- Gemini requires encrypted connection.
+3.  Gemini server -- the program that makes our capsule available
+    (similar to Nginx for HTTP)
+
+As the gemini user, we can create three different directories to
+simplify the process:
+
+```sh
+mkdir -p ~/gemini/{content,certificate,server}
+```
+
+### Content
+
+This will be the directory where your capsule files will be contained.
+Gemini uses text/gemini markup (in place of HTTP\'s equivalent HTML). It
+heavily borrows from Markdown. Similar to .html or .md, gemini uses .gmi
+as its extension.
+
+To create one gemini file, go inside the `content` directory and create
+one `index.gmi` file.
+
+```sh
+nano gemini/content/index.gmi
+```
+
+We can add the content we want in our Gemini capsule here:
+
+```yaml
+# This is Sample Gemini page
+## With header 1 and header 2
+And a short paragraph like this.
+=> /index.gmi Link to the same page
+```
+
+### TLS certificate
+
+Go to the `certificate` directory which we created earlier and generate
+a TLS certificate using OpenSSL.
+
+```sh
+cd ~/gemini/certificate/
+openssl req -new -subj "/CN=example.org" -x509 -newkey ec -pkeyopt ec_paramgen_curve:prime256v1 -days 3650 -nodes -out cert.pem -keyout key.pem
+```
+
+### Gemini server
+
+#### Download and prepare the server
+
+There are [many gemini server software choices
+available](https://gemini.circumlunar.space/software). We will use
+`agate` server for now. This is a simple gemini server written in Rust.
+
+It\'s a good idea to always get the most recent version, which you can
+see [on the agate releases
+page](https://github.com/mbrubeck/agate/releases). At the time of this
+writing, that is agate v3.1.0 which we will now download. We will
+download it to the `server` directory we made.
+
+```sh
+cd ~/gemini/server
+wget https://github.com/mbrubeck/agate/releases/download/v3.1.0/agate.x86_64-unknown-linux-gnu.gz
+```
+
+Unzip the gz, then rename and make it executable:
+
+```sh
+gunzip agate.x86_64-unknown-linux-gnu.gz
+mv agate.x86_64-unknown-linux-gnu agate-server
+chmod +x agate-server
+```
+
+#### Create a system service
+
+Now we need to create a systemd service to autostart and manage agate.
+The gemini user does not have permission to do this, so press <kbd>ctrl-d</kbd>
+to log out of the gemini user and return to root. As root, create the
+file below by opening it in your text editor (nano, vim, etc.):
+
+```sh
+nano /etc/systemd/system/agate.service
+```
+
+Add the following content to the file **customizing highlighted text**
+to your use.
+
+```systemd
+[Unit]
+Description=agate
+After=network.target
+
+[Service]
+User=gemini
+Type=simple
+ExecStart=/home/gemini/gemini/server/agate-server --content /home/gemini/gemini/content --certs /home/gemini/gemini/certificate/ --hostname example.org --lang en-US
+
+[Install]
+WantedBy=default.target
+```
+
+Now we are ready to run server. Enable and run agate server.
+
+```sh
+systemctl enable agate
+systemctl start agate
+```
+
+#### Firewall
+
+Lastly, if you have a firewall running, remember to open port 1965,
+which is the port number used by gemini:
+
+```sh
+ufw allow 1965
+```
+
+## Finalization
+
+Now your server should be running. If everything went okay, you can
+access your gemini capsule via any gemini client with a url like this:
+
+```txt
+gemini://example.org
+```
+
+Sample gemini site for reference:
+
+```txt
+gemini://gemini.circumlunar.space
+```
+
+Enjoy your first gemini capsule.
+
+For information about how to write in \"gemtext\" the markup language in
+Gemini, see this site:
+<https://gemini.circumlunar.space/docs/gemtext.gmi>. As you might guess,
+it also has an analogous gemini capsule here:
+gemini://gemini.circumlunar.space/docs/gemtext.gmi
+
+------------------------------------------------------------------------
+
+*Written by [nihar.page](https://nihar.page)*