### Detection Filter with Grouped Expressions

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

This example illustrates using parentheses to group expressions within a detection filter, demonstrating a negated OR condition for IP ranges.

```shell
!(addr-in(10.0.0.0/8) || addr-in(192.168.0.0/16))
```

--------------------------------

### Run from Source with Go

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

Run the Cloudflare DDNS updater directly from its Go source code. This requires the Go toolchain to be installed. Set the CLOUDFLARE_API_TOKEN, DOMAINS, and PROXIED environment variables.

```bash
CLOUDFLARE_API_TOKEN=YOUR-CLOUDFLARE-API-TOKEN \
  DOMAINS=example.org,www.example.org,example.io \
  PROXIED=true \
  go run github.com/favonia/cloudflare-ddns/cmd/ddns@latest
```

--------------------------------

### IPv4 Detection Filter Example

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

This example demonstrates how to configure an IPv4 detection filter to keep only addresses within a specific CIDR range.

```shell
IP4_DETECTION_FILTER=addr-in(198.51.100.0/24)
```

--------------------------------

### Docker Compose Setup with File-Based IPs for Testing

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

Sets up the updater to read IP addresses from local files (ip4.txt, ip6.txt) for testing simulated IP changes. Ensure the files exist and contain one IP per line. Remove test files and volumes after testing.

```yaml
environment:
  - DOMAINS=ddns-test.example.org
  - IP4_PROVIDER=file:/ip4.txt
  - IP6_PROVIDER=file:/ip6.txt
volumes:
  - $PWD/ip4.txt:/ip4.txt
  - $PWD/ip6.txt:/ip6.txt
```

--------------------------------

### IPv6 Detection Filter with Negation

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

This example demonstrates an IPv6 detection filter that excludes addresses within a specific private range.

```shell
IP6_DETECTION_FILTER=!addr-in(fc00::/7)
```

--------------------------------

### Docker Compose Setup with Static IPs for Testing

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

Configures the updater to use static IP addresses for validation and testing. This is useful for testing without waiting for real IP changes. Remember to switch to production values after testing.

```yaml
environment:
  - DOMAINS=ddns-test.example.org
  - IP4_PROVIDER=static:203.0.113.10
  - IP6_PROVIDER=static:2001:db8::10
```

--------------------------------

### IPv4 Detection Filter with OR Condition

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

This example shows an IPv4 detection filter that keeps addresses within a CIDR range OR matching a specific IP address.

```shell
IP4_DETECTION_FILTER=addr-in(198.51.100.0/24) || addr-in(203.0.113.7/32)
```

--------------------------------

### Configure cloudflare_ddns environment variables on OpenBSD

Source: https://github.com/favonia/cloudflare-ddns/blob/main/contrib/README.markdown

Define environment variables for the cloudflare_ddns daemon in /etc/login.conf. Ensure values are not quoted. This example sets EMOJI to false and specifies API token and domains.

```sh
cloudflare_ddns:\
	:setenv=EMOJI=false,CLOUDFLARE_API_TOKEN=YOUR-CLOUDFLARE-API-TOKEN,DOMAINS=YOUR-DOMAINS:\
	:tc=daemon:
```

--------------------------------

### Static IP Address Provider

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

Uses explicit IP addresses or CIDR notation as a fixed set, separated by commas. Primarily for tests, debugging, and special fixed-input setups.

```text
static:<ip1>,<ip2>,...
```

--------------------------------

### Multi-line Text Format for IP Addresses

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

A line-based text format for multiple IP addresses or CIDR notations, used by URL and file providers. Blank lines are ignored, and '#' starts a comment.

```txt
# Bare addresses
198.51.100.1
198.51.100.2

# Addresses in CIDR notation
198.51.100.0/24
198.51.100.128/25  # inline comments are supported
```

--------------------------------

### Build and Type-Check Hostid6 Proofs

Source: https://github.com/favonia/cloudflare-ddns/blob/main/proofs/README.markdown

Builds the Hostid6 component in Lean 4, which type-checks all theorems. A 'sorry' in a proof will result in a build warning.

```sh
cd proofs && lake build Hostid6
```

--------------------------------

### Run Docker Image

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

Execute the Cloudflare DDNS updater as a Docker container. Ensure you have a Cloudflare API token with appropriate permissions and set the DOMAINS and PROXIED environment variables.

```bash
docker run \
  --network host \
  -e CLOUDFLARE_API_TOKEN=YOUR-CLOUDFLARE-API-TOKEN \
  -e DOMAINS=example.org,www.example.org,example.io \
  -e PROXIED=true \
  favonia/cloudflare-ddns:1
```

--------------------------------

### Pull and Run Cloudflare DDNS Container

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

Pulls the latest Docker image for cloudflare-ddns and starts the container in detached mode. Use 'docker-compose logs cloudflare-ddns' to check its status.

```bash
docker-compose pull cloudflare-ddns
docker-compose up --detach --build cloudflare-ddns
```

--------------------------------

### Build and Run the Oracle Binary

Source: https://github.com/favonia/cloudflare-ddns/blob/main/proofs/README.markdown

Builds the standalone oracle binary used for differential testing. This binary acts as a persistent process for request-response interactions.

```sh
cd proofs && lake build oracle
```

--------------------------------

### Create cloudflare_ddns user on OpenBSD

Source: https://github.com/favonia/cloudflare-ddns/blob/main/contrib/README.markdown

Use this command to create a dedicated user for the cloudflare-ddns daemon with no login shell and a home directory at /var/empty.

```sh
useradd -s /sbin/nologin -d /var/empty _cloudflare_ddns
```

--------------------------------

### Run Differential Test with Lean Oracle

Source: https://github.com/favonia/cloudflare-ddns/blob/main/proofs/README.markdown

Executes a differential test comparing the hostid6.Derive Go implementation against the Lean oracle. Requires the oracle binary to be built and available.

```sh
cd proofs && lake build oracle && cd ..
HOSTID6_LEAN_ORACLE="$PWD/proofs/.lake/build/bin/oracle" go test -tags lean_oracle ./internal/hostid6/...
```

--------------------------------

### Docker Compose Setup to Reconcile Manual DNS Edits

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

Disables the cache for Cloudflare API responses by setting CACHE_EXPIRATION to '1ns'. This allows the updater to immediately reconcile DNS records changed directly in Cloudflare. Restore the default setting afterward.

```yaml
environment:
  - CACHE_EXPIRATION=1ns
```

--------------------------------

### Detection Lifecycle Placement

Source: https://github.com/favonia/cloudflare-ddns/blob/main/docs/designs/features/detection-filter.markdown

Illustrates where the detection filter is applied within the detection and derivation lifecycle. It runs after provider output normalization and before derivation.

```text
detection: provider -> normalization -> filter
derivation -> reconciliation
```

--------------------------------

### Static Empty Provider

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

Clears existing managed content for the selected IP family. Use this to reset configurations without restarting the updater.

```text
static.empty
```

--------------------------------

### Verify Docker Image with Cosign

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

You can verify that the Docker images were built from this repository using cosign. This command checks the image identity and OIDC issuer.

```bash
cosign verify favonia/cloudflare-ddns:1 \
  --certificate-identity-regexp https://github.com/favonia/cloudflare-ddns/ \
  --certificate-oidc-issuer https://token.actions.githubusercontent.com
```

--------------------------------

### None Provider

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

Stops managing the specified IP family for the current run, preserving existing managed DNS records and WAF list items.

```text
none
```

--------------------------------

### Test Cloudflare Connectivity with Alpine

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

Use these commands to test DNS resolution and HTTPS connectivity to Cloudflare from within a Docker environment. This helps diagnose network issues if IP detection fails.

```bash
docker run --rm alpine nslookup api.cloudflare.com
```

```bash
docker run --rm alpine wget -qO- https://api.cloudflare.com/cdn-cgi/trace
```

--------------------------------

### Per-domain IPv6 Host ID Configuration

Source: https://github.com/favonia/cloudflare-ddns/blob/main/CHANGELOG.markdown

Configure specific IPv6 host IDs for domains, allow preserving detected host IDs, or compute EUI-64 host IDs from MAC addresses.

```shell
IP6_DOMAINS=sub.example.com{hostid6=::2}
```

```shell
IP6_DOMAINS=sub.example.com{hostid6=preserve}
```

```shell
IP6_DOMAINS=sub.example.com{hostid6=mac(77:cc:a7:f9:45:94)}
```

```shell
DOMAINS=sub1.example.com{hostid6=::aad1},sub2.example.com{hostid6=preserve}
```

--------------------------------

### Verify Hostid6 Changes

Source: https://github.com/favonia/cloudflare-ddns/blob/main/proofs/README.markdown

A maintenance rule requiring verification of Hostid6 changes by rebuilding the Lean proofs and running the differential test. This ensures consistency between the Go implementation and its formal model.

```sh
cd proofs && lake build Hostid6   # type-checks every theorem; warns on any sorry
HOSTID6_LEAN_ORACLE="$PWD/proofs/.lake/build/bin/oracle" go test -tags lean_oracle ./internal/hostid6/...
```

--------------------------------

### URL Provider with IPv6 Connection

Source: https://github.com/favonia/cloudflare-ddns/blob/main/README.markdown

Fetches the IP address from a URL, always connecting to that URL over IPv6. Supports CIDR notation and multiple-address text format.

```text
url.via6:<url>
```

--------------------------------

### Configuring Record Comment in Cloudflare DDNS

Source: https://github.com/favonia/cloudflare-ddns/blob/main/CHANGELOG.markdown

This snippet demonstrates how to configure the comment for newly created DNS records. By default, the comment is empty, but it can be set using the RECORD_COMMENT environment variable to restore previous behavior.

```bash
RECORD_COMMENT=Created by cloudflare-ddns
```