Added an openbsd article and simplified all useless relref

content/blog/OpenBSD/relayd-httpd-example.md

@@ -0,0 +1,96 @@
+---
+title: OpenBSD relayd/httpd web server example
+date: 2021-02-10
+description: a detailed answer to a question on reddit
+tags:
+  - OpenBSD
+---
+
+## Introduction
+
+[Someone on reddit had trouble](https://www.reddit.com/r/openbsd/comments/lh4yl9/relaydhttpd_reverse_proxy_for_synapse_with/) with how `relayd` and `httpd` work together on OpenBSD. Those are two great components of the OpenBSD base system that take a different approach than the traditional web servers like `Nginx` or `Apache`, I wrote a complete example adapted from my own working configurations.
+
+The goal was to have a relayd configuration that would serve urls like `https://example.com/` with the static website content from httpd, and proxy traffic to urls like https://chat.example.com/ to a synapse server running on `localhost:8008`. Hopefully my working example can provide a better understanding of the idea behind the couple relayd/httpd.
+
+## The httpd configuration
+
+{{< highlight txt >}}
+prefork 5
+
+server "example.com" {
+    alias "chat.example.com"
+    listen on * port 80
+    location "/.well-known/acme-challenge/*" {
+            root "/acme"
+            request strip 2
+    }
+    location * {
+            block return 301 "https://$HTTP_HOST$REQUEST_URI"
+    }
+}
+
+server "example.com" {
+    listen on * port 8080
+    location * {
+            root "/htdocs/www/public/"
+    }
+}
+{{< /highlight >}}
+
+## The relayd configuration
+
+{{< highlight txt >}}
+log state changes
+log connection errors
+prefork 5
+
+table <httpd> { 127.0.0.1 }
+table <synapse> { 127.0.0.1 }
+
+http protocol "wwwsecure" {
+    tls keypair "example.com"
+    tls keypair "chat.example.com"
+
+    # Return HTTP/HTML error pages to the client
+    return error
+    # you may want to remove this depending on your use case
+    #match request header set "Connection" value "close"
+
+    # your web application might need these headers
+    match request header set "X-Forwarded-For" value "$REMOTE_ADDR"
+    match request header set "X-Forwarded-By" value "$SERVER_ADDR:$SERVER_PORT"
+
+    # set best practice security headers
+    # use https://securityheaders.com to check
+    # and modify as needed
+    match response header remove "Server"
+    match response header append "Strict-Transport-Security" value "max-age=31536000; includeSubDomains"
+    match response header append "X-Frame-Options" value "SAMEORIGIN"
+    match response header append "X-XSS-Protection" value "1; mode=block"
+    match response header append "X-Content-Type-Options" value "nosniff"
+    match response header append "Referrer-Policy" value "strict-origin"
+    match response header append "Content-Security-Policy" value "default-src https:; style-src 'self' \
+      'unsafe-inline'; font-src 'self' data:; script-src 'self' 'unsafe-inline' 'unsafe-eval'"
+    match response header append "Permissions-Policy" value "accelerometer=(none), camera=(none), \
+      geolocation=(none), gyroscope=(none), magnetometer=(none), microphone=(none), payment=(none), usb=(none)"
+
+    # set recommended tcp options
+    tcp { nodelay, sack, socket buffer 65536, backlog 100 }
+
+    pass  request  quick  header  "Host"  value  "example.com"       forward  to  <httpd>
+    pass  request  quick  header  "Host"  value  "chat.example.com"  forward  to  <synapse>
+}
+
+relay "wwwsecure" {
+    listen on 0.0.0.0 port 443 tls
+    protocol wwwsecure
+    forward to <httpd> port 8080
+    forward to <synapse> port 8008
+}
+relay "wwwsecure6" {
+    listen on :: port 443 tls
+    protocol wwwsecure
+    forward to <httpd> port 8080
+    forward to <synapse> port 8008
+}
+{{< /highlight >}}