docs: kebab-case all markdown filenames

Author: jeboehm

.env.dist

@@ -1,4 +1,4 @@
-# Documentation available in docs/ENVIRONMENT_VARIABLES.md
+# Documentation available in docs/environment-variables.md
 #
 
 # Database credentials

.mkdocs.yaml

@@ -16,30 +16,30 @@ exclude_docs: |
 nav:
   - Welcome: README.md
   - Quick Start:
-      - INSTALLATION.md
-      - UPGRADE.md
+      - installation.md
+      - upgrade.md
   - Configuration:
-      - ENVIRONMENT_VARIABLES.md
-      - DNS_CONFIGURATION.md
-      - EXTERNAL_MYSQL.md
-      - RELAYHOST.md
-      - LOCAL_ADDRESS_EXTENSION.md
-      - PHP_SESSIONS.md
-      - REVERSE_PROXY.md
-      - ROUNDCUBE.md
-      - TLS.md
+      - environment-variables.md
+      - dns-configuration.md
+      - external-mysql.md
+      - relayhost.md
+      - local-address-extension.md
+      - php-sessions.md
+      - reverse-proxy.md
+      - roundcube.md
+      - tls.md
   - Administration:
       - manage-domains.md
       - manage-users.md
       - manage-aliases.md
       - manage-fetchmail.md
-      - DKIM_SIGNING.md
+      - dkim-signing.md
   - Recipes:
       - Docker:
           - Traefik Reverse Proxy: https://github.com/jeboehm/docker-mailserver/tree/main/docs/example-configs/compose/traefik-reverse-proxy
       - Kubernetes:
           - External Database and HTTPS Ingress: https://github.com/jeboehm/docker-mailserver/tree/main/docs/example-configs/kustomize/external-db-and-https-ingress
   - Development:
-      - ARCHITECTURE.md
-      - DEVELOPMENT.md
+      - architecture.md
+      - development.md
   - Issues: https://github.com/jeboehm/docker-mailserver/issues

README.md

@@ -39,7 +39,7 @@ See the [documentation](https://jeboehm.github.io/docker-mailserver/) for a comp
 
 `docker-mailserver` can be set up using Docker or Kubernetes.
 
-For detailed installation instructions, see the [Installation Guide](https://jeboehm.github.io/docker-mailserver/INSTALLATION/) in the documentation.
+For detailed installation instructions, see the [Installation Guide](https://jeboehm.github.io/docker-mailserver/installation/) in the documentation.
 
 ## Screenshots
 

docs/README.md

@@ -28,8 +28,8 @@ This project enables you to operate your own email services, providing independe
 
 ## Quick Start
 
-1. **[Installation Guide](INSTALLATION.md)** - Get started with Docker or Kubernetes deployment
-2. **[Upgrade Guide](UPGRADE.md)** - Upgrade procedures and version migration notes
+1. **[Installation Guide](installation.md)** - Get started with Docker or Kubernetes deployment
+2. **[Upgrade Guide](upgrade.md)** - Upgrade procedures and version migration notes
 
 ## Service Architecture
 
@@ -45,7 +45,7 @@ The mailserver consists of multiple microservices:
 - **Unbound** - DNS resolver for the filter service
 - **Fetchmail** - External mail retrieval (optional)
 
-See [Architecture Documentation](ARCHITECTURE.md) for detailed information.
+See [Architecture Documentation](architecture.md) for detailed information.
 
 ## Getting Help
 

docs/ARCHITECTURE.md docs/architecture.mddocs/ARCHITECTURE.md renamed to docs/architecture.md

@@ -16,11 +16,11 @@ The mailserver requires several DNS record types to operate correctly:
 
 The Mail Exchange (MX) record directs incoming emails to your mailserver. This is the primary DNS record that tells other mail servers where to deliver emails for your domain.
 
-### Configuration
+### MX Record Configuration
 
 Create an MX record in your domain's DNS zone:
 
-```
+```text
 Type: MX
 Name: @ (or your domain name)
 Priority: 10
@@ -29,15 +29,15 @@ Value: mail.example.com
 
 Replace `mail.example.com` with the value configured in the `MAILNAME` environment variable. The priority value (10 in this example) determines the order when multiple MX records exist. Lower numbers have higher priority.
 
-### Example
+### MX Record Example
 
 For domain `example.com` with mailserver hostname `mail.example.com`:
 
-```
+```text
 example.com.    IN    MX    10    mail.example.com.
 ```
 
-### Verification
+### MX Record Verification
 
 Verify the MX record using DNS lookup tools:
 
@@ -51,11 +51,11 @@ nslookup -type=MX example.com
 
 A and AAAA records resolve the mailserver hostname to IPv4 and IPv6 addresses respectively. These records are required for the MX record to function, as the MX record points to a hostname that must resolve to an IP address.
 
-### Configuration
+### A/AAAA Record Configuration
 
 Create A and AAAA records for your mailserver hostname:
 
-```
+```text
 Type: A
 Name: mail (or your mailserver hostname without domain)
 Value: 192.0.2.1
@@ -67,16 +67,16 @@ Value: 2001:db8::1
 
 Replace the IP addresses with your mailserver's actual IPv4 and IPv6 addresses. If your mailserver only has IPv4, you can omit the AAAA record, though IPv6 is recommended for modern email infrastructure.
 
-### Example
+### A/AAAA Record Example
 
 For mailserver hostname `mail.example.com`:
 
-```
+```text
 mail.example.com.    IN    A        192.0.2.1
 mail.example.com.    IN    AAAA    2001:db8::1
 ```
 
-### Verification
+### A/AAAA Record Verification
 
 Verify the A and AAAA records:
 
@@ -91,11 +91,11 @@ nslookup mail.example.com
 
 The Sender Policy Framework (SPF) record authorizes your mailserver to send emails on behalf of your domain. SPF helps prevent email spoofing by specifying which mail servers are allowed to send emails for your domain.
 
-### Configuration
+### SPF Record Configuration
 
 Create a TXT record with SPF policy:
 
-```
+```text
 Type: TXT
 Name: @ (or your domain name)
 Value: v=spf1 mx a ip4:192.0.2.1 ip6:2001:db8::1 ~all
@@ -113,15 +113,15 @@ Common SPF mechanisms used in mailserver configurations:
 - `~all`: Soft fail for all other sources (recommended during testing)
 - `-all`: Hard fail for all other sources (recommended for production)
 
-### Example
+### SPF Record Example
 
 For domain `example.com` with mailserver at `mail.example.com`:
 
-```
+```text
 example.com.    IN    TXT    "v=spf1 mx a ip4:192.0.2.1 ~all"
 ```
 
-### Verification
+### SPF Record Verification
 
 Verify the SPF record:
 
@@ -136,7 +136,7 @@ SPF records must be published as TXT records. Some DNS providers may also suppor
 
 DomainKeys Identified Mail (DKIM) records publish the public key used to verify email signatures. DKIM signing is configured through the management interface, which generates the DNS TXT record that must be published.
 
-### Configuration
+### DKIM Record Configuration
 
 DKIM records are generated through the management interface:
 
@@ -151,41 +151,41 @@ DKIM records are generated through the management interface:
 
 DKIM records use a specific subdomain format:
 
-```
+```text
 Type: TXT
 Name: default._domainkey (or selector._domainkey)
 Value: v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC...
 ```
 
 The record name includes a selector (typically `default`) and the `_domainkey` subdomain. The value contains the DKIM version, key type, and public key.
 
-### Example
+### DKIM Record Example
 
 For domain `example.com` with selector `default`:
 
-```
+```text
 default._domainkey.example.com.    IN    TXT    "v=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC..."
 ```
 
-### Verification
+### DKIM Record Verification
 
 After publishing the DKIM record, verify it through the management interface. The interface checks DNS propagation and validates the record format. You can also verify manually:
 
 ```bash
 dig TXT default._domainkey.example.com
 ```
 
-See [DKIM Signing](DKIM_SIGNING.md) for detailed DKIM configuration instructions.
+See [DKIM Signing](dkim-signing.md) for detailed DKIM configuration instructions.
 
 ## DMARC Record
 
 Domain-based Message Authentication, Reporting & Conformance (DMARC) records define email authentication policy and enable reporting. DMARC works in conjunction with SPF and DKIM to provide comprehensive email authentication.
 
-### Configuration
+### DMARC Record Configuration
 
 Create a TXT record with DMARC policy:
 
-```
+```text
 Type: TXT
 Name: _dmarc
 Value: v=DMARC1; p=none; rua=mailto:[email protected]
@@ -214,23 +214,23 @@ Common DMARC policy settings:
 
 **Monitoring mode** (recommended for initial deployment):
 
-```
+```text
 _dmarc.example.com.    IN    TXT    "v=DMARC1; p=none; rua=mailto:[email protected]"
 ```
 
 **Quarantine mode** (after monitoring period):
 
-```
+```text
 _dmarc.example.com.    IN    TXT    "v=DMARC1; p=quarantine; rua=mailto:[email protected]; pct=100"
 ```
 
 **Reject mode** (production, after validation):
 
-```
+```text
 _dmarc.example.com.    IN    TXT    "v=DMARC1; p=reject; rua=mailto:[email protected]; aspf=r; adkim=r"
 ```
 
-### Verification
+### DMARC Record Verification
 
 Verify the DMARC record:
 
@@ -242,37 +242,41 @@ dig TXT _dmarc.example.com
 
 For a complete mailserver setup, configure the following DNS records:
 
-| Record Type | Name | Value | Purpose |
-|------------|------|-------|---------|
-| MX | `@` | `10 mail.example.com` | Direct incoming emails |
-| A | `mail` | `192.0.2.1` | Resolve mailserver hostname (IPv4) |
-| AAAA | `mail` | `2001:db8::1` | Resolve mailserver hostname (IPv6) |
-| TXT (SPF) | `@` | `v=spf1 mx a ~all` | Authorize sending servers |
-| TXT (DKIM) | `default._domainkey` | `v=DKIM1; k=rsa; p=...` | Email signature verification |
-| TXT (DMARC) | `_dmarc` | `v=DMARC1; p=none; rua=...` | Authentication policy |
+| Record Type | Name                 | Value                       | Purpose                            |
+| ----------- | -------------------- | --------------------------- | ---------------------------------- |
+| MX          | `@`                  | `10 mail.example.com`       | Direct incoming emails             |
+| A           | `mail`               | `192.0.2.1`                 | Resolve mailserver hostname (IPv4) |
+| AAAA        | `mail`               | `2001:db8::1`               | Resolve mailserver hostname (IPv6) |
+| TXT (SPF)   | `@`                  | `v=spf1 mx a ~all`          | Authorize sending servers          |
+| TXT (DKIM)  | `default._domainkey` | `v=DKIM1; k=rsa; p=...`     | Email signature verification       |
+| TXT (DMARC) | `_dmarc`             | `v=DMARC1; p=none; rua=...` | Authentication policy              |
 
 ## Troubleshooting
 
 ### Common Issues
 
 **Emails not being received:**
+
 - Verify MX record points to correct hostname
 - Ensure A/AAAA records resolve the mailserver hostname
 - Check firewall rules allow connections on port 25
 
 **Emails marked as spam:**
+
 - Verify SPF record is correctly configured
 - Ensure DKIM record is published and verified
 - Check DMARC policy is not too restrictive during initial setup
 - Review DMARC reports for authentication failures
 
 **DKIM verification failures:**
+
 - Verify DKIM DNS record is published correctly
 - Check DNS propagation is complete
 - Ensure the selector matches between DNS and mailserver configuration
 - Verify the public key in DNS matches the private key in mailserver
 
 **SPF failures:**
+
 - Verify all sending IP addresses are included in SPF record
 - Check for syntax errors in SPF record
 - Ensure SPF record is published as TXT record type