Merge pull request 'Use dynamic cloudflare trusted_proxies IP source' (#5) from caddy-dynamic-cf-ip into main

Reviewed-on: #5

Caddyfile

@@ -15,34 +15,19 @@
 	# X-Forwarded-For) are honoured only when the request actually comes from
 	# Cloudflare. This prevents header spoofing from any other source.
 	#
-	# Ranges from https://www.cloudflare.com/ips-v4/ and /ips-v6/ .
+	# The `cloudflare` IP source (WeidiDeng/caddy-cloudflare-ip, baked into the
-	# Keep in sync when Cloudflare updates them (rarely). If you rebuild
+	# caddy-cf image) auto-fetches the ranges from cloudflare.com/ips-v4 and
-	# caddy-cf with the caddy-dynamic-cloudflare / caddy-cloudflare-ip plugin,
+	# /ips-v6 and refreshes them periodically, so there's no static list to
-	# this static list can be replaced with `trusted_proxies cloudflare`.
+	# keep in sync.
 	servers {
-		trusted_proxies static \
+		trusted_proxies cloudflare {
- 173.245.48.0/20 \
+			interval 12h
- 103.21.244.0/22 \
+			timeout 15s
- 103.22.200.0/22 \
+		}
- 103.31.4.0/22 \
+		# Read the real visitor IP from these headers (only honoured for
- 141.101.64.0/18 \
+		# requests from trusted_proxies above). Cf-Connecting-Ip is
- 108.162.192.0/18 \
+		# Cloudflare's single authoritative end-user IP; X-Forwarded-For is
- 190.93.240.0/20 \
+		# the fallback if a request ever arrives without the CF header.
- 188.114.96.0/20 \
- 197.234.240.0/22 \
- 198.41.128.0/17 \
- 162.158.0.0/15 \
- 104.16.0.0/13 \
- 104.24.0.0/14 \
- 172.64.0.0/13 \
- 131.0.72.0/22 \
- 2400:cb00::/32 \
- 2606:4700::/32 \
- 2803:f800::/32 \
- 2405:b500::/32 \
- 2405:8100::/32 \
- 2a06:98c0::/29 \
- 2c0f:f248::/32
 		client_ip_headers Cf-Connecting-Ip X-Forwarded-For
 	}
 }

docs/caddy-reverse-proxy.md

@@ -99,14 +99,31 @@ committed [`Caddyfile`](../Caddyfile) at the repo root; copy it to the
   i.e. a **blank page**.
 - **`encode zstd gzip`** — compression happens here (SWS has it disabled).
 - **`header { ... }`** — security headers (SWS has them disabled).
-- **`trusted_proxies static <Cloudflare ranges>`** + **`client_ip_headers
+- **`trusted_proxies cloudflare { ... }`** + **`client_ip_headers
   Cf-Connecting-Ip X-Forwarded-For`** — so the real visitor IP is used for
   logging/matchers, but only when the request genuinely comes from Cloudflare
-  (prevents header spoofing from any other source). The ranges come from
+  (prevents header spoofing from any other source). The `cloudflare` IP source
-  <https://www.cloudflare.com/ips-v4/> and <https://www.cloudflare.com/ips-v6/>;
+  ([WeidiDeng/caddy-cloudflare-ip](https://github.com/WeidiDeng/caddy-cloudflare-ip),
-  keep them in sync when Cloudflare updates them. If `caddy-cf` is rebuilt with
+  baked into the `caddy-cf` image) auto-fetches the ranges from
-  the `caddy-cloudflare-ip` plugin, the static list can be replaced with
+  <https://www.cloudflare.com/ips-v4/> and <https://www.cloudflare.com/ips-v6/>
-  `trusted_proxies cloudflare`.
+  and refreshes them on the configured `interval`, so there is no static list to
+  maintain:
+
+  ```caddy
+  trusted_proxies cloudflare {
+  	interval 12h
+  	timeout 15s
+  }
+  ```
+
+  `client_ip_headers` lists which header holds the real visitor IP:
+  `Cf-Connecting-Ip` is Cloudflare's single authoritative end-user IP, with
+  `X-Forwarded-For` as the fallback. It is only trusted for requests coming from
+  the `trusted_proxies` above.
+
+  > If you ever run without the `caddy-cloudflare-ip` plugin, you can instead
+  > pin the static ranges with `trusted_proxies static <ip/cidr ...>` copied
+  > from the Cloudflare IP pages, but then you must keep them in sync manually.
 
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