### Add Helm Repository and Install Postfix Chart

Source: https://github.com/bokysan/docker-postfix/blob/master/README.md

Add the Postfix Helm chart repository and then upgrade or install the chart. This example disables persistence and sets allowed sender domains to 'example.com'.

```shell
helm repo add bokysan https://bokysan.github.io/docker-postfix/
helm upgrade --install --set persistence.enabled=false --set config.general.ALLOWED_SENDER_DOMAINS=example.com mail bokysan/mail
```

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

### Using Existing DKIM Keys Example

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/dkim-functions.md

This example shows how to configure DKIM signing using pre-existing private and public key files. Ensure the keys are located at `/etc/opendkim/keys/{domain}.private` and `/etc/opendkim/keys/{domain}.txt`.

```bash
# Pre-existing keys at:
# /etc/opendkim/keys/example.com.private
# /etc/opendkim/keys/example.com.txt

export ALLOWED_SENDER_DOMAINS="example.com"
postfix_setup_dkim
# Configures DKIM using existing keys
```

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

### Example: Run container with JSON logging

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/logging-functions.md

Demonstrates how to run a Postfix container with JSON-formatted syslog output enabled.

```bash
docker run -e LOG_FORMAT=json boky/postfix
# Produces: JSON-formatted syslog output
```

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

### HashFilter Query String Examples

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/email-anonymizer.md

Provides examples of query strings for configuring the HashFilter. These demonstrate different combinations of parameters like salt, short_sha, prefix, split, and case_sensitive.

```text
HashFilter?salt=my-secret-salt&short_sha=true&prefix=h:
HashFilter?salt=org-salt&split=true&case_sensitive=false
```

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

### OpenDKIM Configuration Example

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/types.md

A sample OpenDKIM configuration file showing common parameters for setting up signing and verification modes.

```ini
Mode                    sv
Socket                  inet:8891@127.0.0.1
PidFile                 /var/run/opendkim/opendkim.pid
UserID                  opendkim:opendkim
LogWhy                  no
Syslog                  yes
```

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

### HashFilter Initialization Example

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/email-anonymizer.md

Shows how to initialize the HashFilter with required and optional parameters. The 'salt' parameter is mandatory.

```python
def init(self, args: 'dict[str, list[str]]') -> None:
    # Requires 'salt' parameter
```

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

### Example Host Connection to Submission Port

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/networking.md

Example of connecting to the Postfix submission port (587) from the host machine using telnet.

```bash
# From host:
telnet localhost 587
# Response: 220 mail.example.com ESMTP Postfix
```

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

### Dockerfile Source Reference Example

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/README.md

Illustrates how Dockerfile source locations are referenced, including file path and line numbers.

```dockerfile
Dockerfile:66
```

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

### Example: Warning Logged During Distribution Switch

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/database-upgrade-functions.md

This is an example of a warning message logged by the postfix_upgrade_daemon_directory function when it detects a switch from Debian/Ubuntu to Alpine and is about to change the daemon_directory.

```bash
WARN: You're switching from Debian/Ubuntu to Alpine. Changing daemon_directory...
```

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

### Postfix Main Configuration Example

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/types.md

A sample of the Postfix main.cf configuration file, showing key-value pairs for hostname, networks, relay host, and SASL authentication.

```postfix
myhostname = mail.example.com
mynetworks = 127.0.0.0/8 10.0.0.0/8
relayhost = [smtp.gmail.com]:587
smtp_sasl_auth_enable = yes
```

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

### Example: Smart email anonymization

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/logging-functions.md

Runs a Postfix container with 'smart' email anonymization enabled, showing the resulting log format.

```bash
docker run -e ANONYMIZE_EMAILS=smart boky/postfix
# Logs: user@example.com → u*r@*.com
```

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

### Auto-generate DKIM Keys Example

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/dkim-functions.md

This example demonstrates how to auto-generate DKIM keys for specified domains. The function will create private and public key files and output the public key records for DNS configuration.

```bash
export DKIM_AUTOGENERATE=1
export ALLOWED_SENDER_DOMAINS="example.com test.org"
export DKIM_SELECTOR="example.com=mail,test.org=dkim"
postfix_setup_dkim
# Generates keys in /etc/opendkim/keys/
# Outputs public key records for DNS
```

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

### Email Anonymizer Filter Examples

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/email-anonymizer.md

Provides examples of command-line invocations for different email anonymizer filters, including default, alias, paranoid, and hash filters with parameters.

```bash
/scripts/email-anonymizer.py                          # SmartFilter (default)

```

```bash
/scripts/email-anonymizer.py default                  # SmartFilter (alias)

```

```bash
/scripts/email-anonymizer.py paranoid                 # ParanoidFilter

```

```bash
/scripts/email-anonymizer.py "HashFilter?salt=xyz"   # HashFilter with parameters

```

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

### Example Usage of Logging Functions

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/utility-functions.md

Demonstrates the usage of various logging functions with different severity levels and includes color variable usage.

```bash
debug "Starting configuration"
info "Hostname is ${emphasis}$HOSTNAME${reset}"
notice "Using default network list"
warn "SKIP_ROOT_SPOOL_CHOWN is set"
error "Configuration failed"
```

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

### HashFilter Hashing Examples

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/email-anonymizer.md

Demonstrates the output of the HashFilter with different configurations. Shows full hash, truncated hash, and separate hashing of local and domain parts.

```text
salt="my-secret"
user@example.com → a1b2c3d4e5f6g7h8i9j0... (full)
user@example.com → a1b2c3d4 (with short_sha=true)

split=true:
  local part (user) → hash1
  domain part (example.com) → hash2
  result → hash1@hash2
```

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

### Standard Postfix Log (Raw)

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/logging-functions.md

Example of a raw Postfix log entry including email addresses.

```log
2026-06-28T11:23:45.123456+00:00 mail postfix/smtp[12345]: ABCDEF: to=<user@example.com>, relay=smtp.gmail.com[142.251.41.108]:587, delay=1.2, delays=0.1/0.2/0.5/0.4, dsn=2.0.0, status=sent (250 2.0.0 OK)
```

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

### Bash Script Source Reference Example

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/README.md

Illustrates how bash script source locations are referenced, including file path and line numbers.

```bash
image_root/scripts/functions.sh:123
```

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

### Startup Sequence Functions

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/README.md

Lists the sequence of functions executed during the startup of the Docker Postfix container. This sequence ensures all necessary setup steps are performed in the correct order.

```shell
1. announce_startup()
2. setup_timezone()
3. check_environment_sane()
4. rsyslog_log_format()
5. logrotate_remove_duplicate_mail_log()
... (31 more)
36. unset_sensitive_variables()
```

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

### Python Script Source Reference Example

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/README.md

Illustrates how python script source locations are referenced, including file path and line numbers.

```python
image_root/scripts/email-anonymizer.py:456
```

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

### Python SMTP Client Example

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/networking.md

Connect to the Postfix service from a Python application using its Kubernetes service DNS name. Ensure the application can resolve and reach the service.

```python
# Python application
import smtplib

smtp = smtplib.SMTP('postfix-mail.default.svc.cluster.local', 587)
```

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

### Example: Debian to Alpine Daemon Directory Switch

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/database-upgrade-functions.md

Illustrates the state of the daemon_directory configuration before and after the postfix_upgrade_daemon_directory function automatically updates it when switching from a Debian-based system to Alpine.

```bash
# In /etc/postfix/main.cf (from Debian)
daemon_directory = /usr/lib/postfix/sbin  # Doesn't exist on Alpine
```

```bash
# Auto-updated by this function
daemon_directory = /usr/libexec/postfix   # Correct path for Alpine
```

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

### Example: Paranoid email anonymization

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/logging-functions.md

Runs a Postfix container with 'paranoid' email anonymization enabled, showing the resulting log format.

```bash
docker run -e ANONYMIZE_EMAILS=paranoid boky/postfix
# Logs: user@example.com → *@*.com
```

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

### Mount Postfix Configuration Directory

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/networking.md

Example of mounting the Postfix configuration directory to persist custom settings like main.cf and master.cf. It's advised to also keep the spool directory separate.

```bash
docker run -v postfix_config:/etc/postfix boky/postfix
```

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

### Run Docker Postfix with Allowed Sender Domains

Source: https://github.com/bokysan/docker-postfix/blob/master/README.md

Use this command to run the Postfix Docker container, specifying allowed sender domains to prevent Postfix from refusing to start due to spam protection. Ensure to replace 'example.com' and 'example.org' with your actual domains.

```shell
docker run --rm --name postfix -e "ALLOWED_SENDER_DOMAINS=example.com example.org" -p 1587:587 boky/postfix
```

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

### Basic Postfix Setup (Direct Delivery)

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/configuration.md

Use this configuration for direct email delivery without any relay host. Ensure your server has a valid hostname and MX records.

```bash
docker run -e ALLOWED_SENDER_DOMAINS="example.com" \
           -p 1587:587 \
           boky/postfix
```

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

### Example: Hash email anonymization with salt

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/logging-functions.md

Runs a Postfix container with 'hash' email anonymization, including a custom salt and short SHA option.

```bash
docker run -e ANONYMIZE_EMAILS="hash?salt=org-secret&short_sha=true" boky/postfix
# Logs: user@example.com → a1b2c3d4
```

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

### Example: No email anonymization

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/logging-functions.md

Runs a Postfix container with anonymization disabled, showing that email addresses remain unchanged in logs.

```bash
docker run -e ANONYMIZE_EMAILS=0 boky/postfix
# Logs: user@example.com (unchanged)
```

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

### Execute Custom Postfix Configuration

Source: https://github.com/bokysan/docker-postfix/blob/master/README.md

Use shell scripts within `/docker-init.d/` to apply custom Postfix configurations. This example demonstrates enabling negative caching for address verification.

```shell
#!/bin/sh
postconf -e "address_verify_negative_cache=yes"
```

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

### Kubernetes StatefulSet for Postfix

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/networking.md

Deploy Postfix as a StatefulSet in Kubernetes. This example configures environment variables for allowed sender domains and relay host, and sets up persistent storage for mail spool.

```yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: postfix
spec:
  serviceName: postfix-mail
  selector:
    matchLabels:
      app: postfix
  template:
    metadata:
      labels:
        app: postfix
    spec:
      containers:
      - name: postfix
        image: boky/postfix:latest
        ports:
        - containerPort: 587
        env:
        - name: ALLOWED_SENDER_DOMAINS
          value: "example.com"
        - name: RELAYHOST
          value: "smtp.gmail.com:587"
        volumeMounts:
        - name: spool
          mountPath: /var/spool/postfix
  volumeClaimTemplates:
  - metadata:
      name: spool
    spec:
      accessModes: ["ReadWriteOnce"]
      resources:
        requests:
          storage: 5Gi
```

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

### OpenDKIM KeyTable Format Example

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/types.md

Defines the format for the KeyTable file, mapping DKIM selectors and domains to their corresponding private key paths. Ensure the path to the private key is readable by the opendkim process.

```text
selector._domainkey.domain.com domain:selector:/path/to/private.key
mail._domainkey.example.com example.com:mail:/etc/opendkim/keys/example.com.private
dkim._domainkey.test.org test.org:dkim:/etc/opendkim/keys/test.org.private
```

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

### Kubernetes Secrets Example

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/configuration.md

Illustrates how to mount Kubernetes secrets as volumes and reference them using environment variables with the `_FILE` suffix. This allows sensitive data to be injected into the Postfix container securely.

```yaml
containers:
  - name: postfix
    env:
    - name: RELAYHOST_PASSWORD_FILE
      value: /var/run/secrets/relay_password
    volumeMounts:
    - name: relay-secret
      mountPath: /var/run/secrets
volumes:
  - name: relay-secret
    secret:
      secretName: relay-password
```

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

### Deploy Postfix with Helm Chart

Source: https://github.com/bokysan/docker-postfix/blob/master/README.md

Deploy the Postfix mail server using the Helm chart. This example disables persistence and allows empty sender domains. Refer to ArtifactHub for more configuration options.

```shell
helm repo add bokysan https://bokysan.github.io/docker-postfix/
helm upgrade --install --set persistence.enabled=false --set config.general.ALLOW_EMPTY_SENDER_DOMAINS=yes mail bokysan/mail
```

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

### OpenDKIM SigningTable Format Example

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/types.md

Illustrates the format for the SigningTable file, which associates email patterns with DKIM identities (selector._domainkey.domain) defined in the KeyTable. Use patterns like '*@domain.com' for broad matching or specific addresses.

```text
*@domain.com selector._domainkey.domain.com
*@example.com mail._domainkey.example.com
*@test.org dkim._domainkey.test.org
```

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

### Run Container with Valid Timezone

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/errors.md

Example of running the Postfix Docker container with a valid timezone specified. This resolves the 'Timezone Not Found' warning.

```bash
docker run -e TZ="America/New_York" boky/postfix
```

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

### SmartFilter Example Usage with Query Parameter

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/email-anonymizer.md

Demonstrates how to use the `mask_symbol` query parameter with `rsyslog` configuration to change the masking character from the default '*' to 'X'.

```bash
rsyslog_config="... default?mask_symbol=X ..."
# Outputs: d*o@*.org becomes dXo@*.org (uses X instead of *)

```

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

### Mount Postfix Spool Directory

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/networking.md

Example of mounting the Postfix spool directory to preserve queued messages across container restarts. This is recommended for mail queue persistence.

```bash
docker run -v postfix_spool:/var/spool/postfix boky/postfix
```

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

### Docker Compose for Inbound Connections

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/networking.md

Example Docker Compose configuration to set up Postfix and an application service on the same network, allowing inbound connections to Postfix on port 587.

```yaml
services:
  app:
    image: myapp
    networks:
      - mail-network  # Same network as Postfix
  
  postfix:
    image: boky/postfix
    environment:
      ALLOWED_SENDER_DOMAINS: example.com
    networks:
      - mail-network
    ports:
      - "587:587"

networks:
  mail-network:
```

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

### Setup External SMTP Relay Host

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/postfix-configuration-functions.md

Configures an external SMTP relay host, including authentication details. Supports Docker Secrets for password management.

```bash
postfix_setup_relayhost()
```

```bash
export RELAYHOST="smtp.gmail.com:587"
export RELAYHOST_USERNAME="user@example.com"
export RELAYHOST_PASSWORD="app-password"
postfix_setup_relayhost
# Configures Gmail relay with authentication
```

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

### Mount OpenDKIM Keys Directory

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/networking.md

Example of mounting the OpenDKIM keys directory to preserve DKIM private and public keys. Ensure private keys are never exposed outside the container.

```bash
docker run -v dkim_keys:/etc/opendkim/keys boky/postfix
```

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

### Setup Timezone from TZ Variable

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/initialization-functions.md

Configures the container's timezone based on the `TZ` environment variable. Creates symlinks and sets the timezone file, warning if the timezone file is not found.

```bash
export TZ="Europe/Amsterdam"
setup_timezone()
```

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

### announce_startup()

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/initialization-functions.md

Prints a startup banner with system and account information. It detects the distribution and displays UIDs/GIDs for postfix and opendkim accounts.

```APIDOC
## announce_startup()

### Description
Prints a startup banner with system and account information. It detects the distribution and displays UIDs/GIDs for postfix and opendkim accounts.

### Method
Shell command

### Endpoint
announce_startup()

### Parameters
None

### Response
None (prints to stdout)

### Output Example:
```
★★★★★ POSTFIX STARTING UP (alpine) ★★★★★
System accounts: postfix=101:104, opendkim=102:105
```
```

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

### Postfix XOAuth2 Post-Configuration

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/authentication-functions.md

Configures the XOAuth2 SASL mechanism in Postfix after initial setup. It detects installed SASL plugins and adjusts the mechanism list if XOAuth2 is not enabled.

```bash
postfix_setup_xoauth2_post_setup()
```

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

### setup_conf()

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/initialization-functions.md

Copies initial Postfix configuration from /etc/postfix.template/ to /etc/postfix/ if the destination does not exist. It ensures that custom configurations are preserved by not overwriting existing files.

```APIDOC
## setup_conf()

### Description
Copies initial Postfix configuration from `/etc/postfix.template/` to `/etc/postfix/` if the destination directory does not exist. This function ensures that custom configurations are preserved by not overwriting existing files.

### Parameters
None

### Returns
None

### Behavior
- Recursively copies missing files/directories from `/etc/postfix.template/` to `/etc/postfix/`.
- Does not overwrite existing files.
- Creates `/etc/postfix/` directory if it is missing.
```

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

### Docker Secrets Example

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/configuration.md

Demonstrates how to use Docker secrets to provide sensitive variables like passwords to the Postfix container. The `_FILE` suffix indicates that the variable's value should be read from the specified file path.

```bash
docker run --secret relay_password \
  -e RELAYHOST_PASSWORD_FILE=/run/secrets/relay_password \
  -e RELAYHOST="smtp.gmail.com:587" \
  boky/postfix
```

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

### Postfix Recipient Restrictions Example

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/types.md

An example of how to integrate the allowed senders check into Postfix's main configuration.

```postfix
smtpd_recipient_restrictions = reject_non_fqdn_recipient,
                               reject_unknown_recipient_domain,
                               check_sender_access lmdb:/etc/postfix/allowed_senders,
                               reject
```

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

### Initialization Functions

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/MANIFEST.txt

Reference for 14 startup initialization functions used to set up the Postfix service.

```APIDOC
## Initialization Functions

### Description
Provides documentation for 14 functions related to the startup and initialization of the Docker Postfix service.

### Usage
Refer to `api-reference/initialization-functions.md` for detailed function signatures, parameters, and examples.
```

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

### Email Anonymizer Filter Validation Examples

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/email-anonymizer.md

Shows examples of valid and invalid filter class names that the email anonymizer script accepts or rejects to prevent injection vulnerabilities.

```python
# Valid:
"SmartFilter"
"custom_filter.MyFilter"

```

```python
# Invalid (rejected):
"__import__(...)"
"os.system(...)"

```

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

### Enable Postfix Chroot Environment

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/initialization-functions.md

Prepares the filesystem for a Postfix chroot environment by copying necessary configuration files and directories. It handles the creation of `/etc/nsswitch.conf` if it's missing, addressing potential issues in containerized environments like Kubernetes.

```bash
postfix_enable_chroot()
```

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

### postfix_enable_chroot()

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/initialization-functions.md

Prepares the filesystem for the Postfix chroot environment by copying necessary configuration files and directories. It also handles the creation of `/etc/nsswitch.conf` to resolve Kubernetes-specific issues.

```APIDOC
## postfix_enable_chroot()

### Description
Prepares the filesystem for the Postfix chroot environment. This function copies essential configuration files and directories into the chroot jail, ensuring Postfix operates correctly in an isolated environment.

### Parameters
#### Environment Variables
- **$POSTFIXD_DIR** (string) - Optional - Defaults to `/var/spool/postfix`. Specifies the Postfix spool directory.
- **$POSTFIXD_ETC** (string) - Optional - Defaults to `$POSTFIXD_DIR/etc`. Specifies the chroot `/etc` directory.
- **$POSTFIXD_ZIF** (string) - Optional - Defaults to `$POSTFIXD_DIR/usr/share/zoneinfo`. Specifies the chroot timezone directory.

### Returns
None

### Files Copied into Chroot
- `/etc/localtime`
- `/etc/nsswitch.conf` (created if missing, fixes Kubernetes issue #71082)
- `/etc/resolv.conf`
- `/etc/services`
- `/etc/host.conf`
- `/etc/hosts`
- `/etc/passwd`
- `/usr/share/zoneinfo/` (all timezones)

### Creates
- `/etc/nsswitch.conf` with content `hosts: files dns` if missing.
```

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

### DKIM Functions

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/MANIFEST.txt

Guides on DKIM key generation and OpenDKIM configuration.

```APIDOC
## DKIM Functions

### Description
Provides functions and instructions for generating DKIM keys and configuring OpenDKIM for email signing.

### Usage
Refer to `api-reference/dkim-functions.md` for detailed guidance on DKIM setup.
```

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

### Announce Startup Banner

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/initialization-functions.md

Prints a startup banner with system and account details. Detects the distribution and displays UIDs/GIDs for Postfix and OpenDKIM.

```bash
announce_startup()
```

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

### Check Postfix Startup Errors

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/errors.md

Review the container's general logs to identify any errors that occurred during the Postfix service startup.

```bash
docker logs <container-id>
```

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

### Create and Initialize Postfix Aliases

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/initialization-functions.md

Creates an empty alias file and generates the binary database. This function is primarily for Postfix validation purposes.

```bash
postfix_create_aliases()
```

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

### postfix_setup_xoauth2_post_setup()

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/authentication-functions.md

Post-configures the XOAuth2 SASL mechanism in Postfix. This function does not take any parameters and relies on settings from `postfix_setup_xoauth2_pre_setup()`. It adjusts SASL configuration based on whether XOAuth2 is enabled and handles different distribution naming conventions.

```APIDOC
## postfix_setup_xoauth2_post_setup()

### Description
Post-configures XOAuth2 SASL mechanism in Postfix. It detects installed SASL plugins and adjusts the mechanism list if XOAuth2 is not enabled, ensuring proper handling of credentials.

### Method
None (Shell function)

### Parameters
None

### Behavior
- Detects installed SASL plugins.
- Removes sasl-xoauth2 from mechanism list if XOAuth2 is not enabled.
- Handles different distro naming conventions.

### Postfix Configuration Set (when XOAuth2 enabled)
```
smtp_sasl_security_options = (empty)
smtp_sasl_mechanism_filter = xoauth2
smtp_tls_session_cache_database = lmdb:${data_directory}/smtp_scache
```

### Postfix Configuration Set (when XOAuth2 disabled)
```
smtp_sasl_mechanism_filter = [list of other mechanisms excluding xoauth2]
```
```

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

### Postfix Log (Anonymized - Hash)

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/logging-functions.md

Example of a Postfix log entry anonymized using the 'hash' format, replacing email addresses with hashes.

```log
2026-06-28T11:23:45.123456+00:00 mail postfix/smtp[12345]: ABCDEF: to=<a1b2c3d4@hash.example>, relay=smtp.gmail.com[142.251.41.108]:587, delay=1.2, delays=0.1/0.2/0.5/0.4, dsn=2.0.0, status=sent (250 2.0.0 OK)
```

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

### postfix_setup_xoauth2_pre_setup()

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/authentication-functions.md

Pre-configures XOAuth2 authentication for relay hosts like Gmail and Google Workspace. It sets up necessary configuration files and token storage for secure authentication.

```APIDOC
## postfix_setup_xoauth2_pre_setup()

### Description
Pre-configures XOAuth2 authentication for relay hosts (Gmail, Google Workspace).

### Method
Shell Function

### Parameters
#### Environment Variables
- **$XOAUTH2_CLIENT_ID** (string) - Conditional - OAuth2 client ID from Google Cloud Console
- **$XOAUTH2_SECRET** (string) - Conditional - OAuth2 client secret
- **$XOAUTH2_TOKEN_ENDPOINT** (string) - No - `https://accounts.google.com/o/oauth2/token` - Google OAuth2 token endpoint
- **$XOAUTH2_INITIAL_ACCESS_TOKEN** (string) - Conditional - Initial access token (only needed on first run)
- **$XOAUTH2_INITIAL_REFRESH_TOKEN** (string) - Conditional - Initial refresh token (only needed on first run)
- **$XOAUTH2_SYSLOG_ON_FAILURE** (string) - No - `no` - Log failures to syslog
- **$XOAUTH2_FULL_TRACE** (string) - No - `no` - Log full trace on failure
- **$RELAYHOST** (string) - Required - Relay host (e.g., `smtp.gmail.com:587`)
- **$RELAYHOST_USERNAME** (string) - Required - Gmail address or service account email

### Returns
None

### Files Created
- `/etc/sasl-xoauth2.conf` — OAuth2 configuration (JSON format)
- `/var/spool/postfix/xoauth2-tokens/$RELAYHOST_USERNAME` — Token file (JSON)

### Token File Format
```json
{
  "access_token": "...",
  "refresh_token": "...",
  "expiry": "0"
}
```

### Errors
- Exits if `$RELAYHOST` or `$RELAYHOST_USERNAME` not set

### Example
```bash
export XOAUTH2_CLIENT_ID="123456789.apps.googleusercontent.com"
export XOAUTH2_SECRET="your-secret-key"
export XOAUTH2_INITIAL_ACCESS_TOKEN="initial-access-token"
export XOAUTH2_INITIAL_REFRESH_TOKEN="initial-refresh-token"
export RELAYHOST="smtp.gmail.com:587"
export RELAYHOST_USERNAME="user@gmail.com"
postfix_setup_xoauth2_pre_setup
```
```

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

### Postfix Log (Anonymized - Paranoid)

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/logging-functions.md

Example of a Postfix log entry anonymized using the 'paranoid' format, completely masking email addresses.

```log
2026-06-28T11:23:45.123456+00:00 mail postfix/smtp[12345]: ABCDEF: to=<*@*.com>, relay=smtp.gmail.com[142.251.41.108]:587, delay=1.2, delays=0.1/0.2/0.5/0.4, dsn=2.0.0, status=sent (250 2.0.0 OK)
```

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

### Postfix Log (Anonymized - Smart)

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/logging-functions.md

Example of a Postfix log entry anonymized using the 'smart' format, partially masking email addresses.

```log
2026-06-28T11:23:45.123456+00:00 mail postfix/smtp[12345]: ABCDEF: to=<u*r@*.com>, relay=smtp.gmail.com[142.251.41.108]:587, delay=1.2, delays=0.1/0.2/0.5/0.4, dsn=2.0.0, status=sent (250 2.0.0 OK)
```

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

### Kubernetes Service Definition for Postfix

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/networking.md

Define a Kubernetes Service to expose your Postfix deployment. This example uses a static cluster IP, which is optional.

```yaml
apiVersion: v1
kind: Service
metadata:
  name: postfix-mail
spec:
  selector:
    app: postfix
  ports:
  - protocol: TCP
    port: 587
    targetPort: 587
    name: submission
  clusterIP: 10.0.0.50  # Static IP optional
```

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

### HashFilter Replacement Method Example

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/email-anonymizer.md

Illustrates the replace method of HashFilter, which generates the hashed email string. It uses HMAC-SHA256 with a user-provided salt.

```python
def replace(self, match: re.match, msg: str) -> str:
    return self.prefix + hash + self.suffix
```

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

### execute_post_init_scripts()

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/initialization-functions.md

Executes custom initialization scripts located in `/docker-init.d/` and `/docker-init.db/` directories. Supports sourcing environment variables for `.sh` files and executing others with `bash`.

```APIDOC
## execute_post_init_scripts()

### Description
Executes custom initialization scripts from `/docker-init.d/` and `/docker-init.db/` directories.

### Method
Shell Function

### Signature
execute_post_init_scripts()

### Parameters
None

### Returns
None

### Script Directories
- `/docker-init.d/` — Recommended mount point for custom scripts
- `/docker-init.db/` — Legacy mount point (deprecated, shows warning)

### Script Execution
- Executable `.sh` files are sourced (inherit environment)
- Non-executable `.sh` files are executed with `bash`
- Other files are ignored

### Example Script
```bash
# Custom init script at /docker-init.d/my-setup.sh
#!/bin/bash
do_postconf -e "my_custom_param=value"
```
```

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

### DKIM Selector Configuration Example

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/dkim-functions.md

Defines custom DKIM selectors for specific domains. If a domain is not explicitly listed, a default selector is used.

```bash
export DKIM_SELECTOR="gmail.com=google,yahoo.com=yahoo,mail"
# gmail.com uses 'google', yahoo.com uses 'yahoo', others use 'mail'
```

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

### postfix_setup_dkim()

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/dkim-functions.md

Configures DKIM signing for allowed sender domains. It can auto-generate missing keys or use existing ones, and sets up Postfix to use OpenDKIM for signing.

```APIDOC
## postfix_setup_dkim()

### Description
Configures DKIM signing for allowed sender domains. It can auto-generate missing keys or use existing ones, and sets up Postfix to use OpenDKIM for signing.

### Function Signature
```bash
postfix_setup_dkim()
```

### Parameters
#### Environment Variables
- **DKIM_AUTOGENERATE** (string) - Optional - Set to non-empty to auto-generate missing keys.
- **ALLOWED_SENDER_DOMAINS** (string) - Conditional - Domains to create DKIM keys for (required if `DKIM_AUTOGENERATE` is set).
- **DKIM_SELECTOR** (string) - Optional - Custom DKIM selector(s) per domain. Format: `domain.com=selector1,example.org=selector2,default_selector` or a bare value for the default selector.

### Returns
None

### Behavior Details
**Auto-Generation (when `$DKIM_AUTOGENERATE` is set):**
- Creates `/etc/opendkim/keys/` directory if missing.
- For each domain in `$ALLOWED_SENDER_DOMAINS`, checks for `/etc/opendkim/keys/{domain}.private`.
- If missing, generates a 2048-bit RSA key using `opendkim-genkey`.
- Fixes hash algorithm header to `h=sha256`.
- Sets permissions: private key `400`, public key `644`.
- Displays public key content for DNS configuration.

**DKIM Configuration (when keys exist):**
- Creates `/var/run/opendkim/` directory.
- Detects OpenDKIM socket from `/etc/opendkim/opendkim.conf`.
- Converts socket format to Postfix milter format.
- Sets Postfix milter configuration (`milter_protocol`, `milter_default_action`, `smtpd_milters`, `non_smtpd_milters`).
- Creates OpenDKIM databases: `/etc/opendkim/TrustedHosts`, `/etc/opendkim/KeyTable`, `/etc/opendkim/SigningTable`.

### Key Files Created
- `/etc/opendkim/keys/{domain}.private` (RSA private key, owner: `opendkim:opendkim`)
- `/etc/opendkim/keys/{domain}.txt` (DKIM public key record in DNS format)

### Example Usage
**Auto-generate keys:**
```bash
export DKIM_AUTOGENERATE=1
export ALLOWED_SENDER_DOMAINS="example.com test.org"
export DKIM_SELECTOR="example.com=mail,test.org=dkim"
postfix_setup_dkim
```

**Using existing keys:**
```bash
export ALLOWED_SENDER_DOMAINS="example.com"
postfix_setup_dkim
```

### DNS Configuration Required
For each domain, add a TXT record similar to:
```
mail._domainkey.example.com. IN TXT "v=DKIM1; h=sha256; k=rsa; p=MIGfMA0..."
```
```

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

### postfix_create_aliases()

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/initialization-functions.md

Creates and initializes the Postfix alias database by generating an empty alias file and then running `postalias` to create the binary database.

```APIDOC
## postfix_create_aliases()

### Description
Creates and initializes the Postfix alias database. This involves creating an empty `/etc/postfix/aliases` file and then running `postalias` to generate the binary database. While the database is not directly used by this image, it is required for Postfix validation.

### Method
Shell Function

### Parameters
None

### Returns
None
```

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

### Initialize Postfix Configuration

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/initialization-functions.md

Copies initial Postfix configuration files from a template directory to the main configuration directory if the destination does not already exist. This function ensures that default configurations are present without overwriting user-defined settings.

```bash
setup_conf()
```

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

### DKIM Selector Configuration Examples

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/configuration.md

Configure DKIM selectors for domain-specific or general use. The `DKIM_SELECTOR` variable accepts a comma-separated list of domain-selector pairs or a single selector for all domains.

```bash
DKIM_SELECTOR="mail"
```

```bash
DKIM_SELECTOR="example.com=google,test.org=dkim,mail"
```

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

### DNS Configuration for DKIM

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/dkim-functions.md

This is an example of the TXT record required in your DNS settings for DKIM to function correctly. Replace the public key 'p=' value with the actual key generated.

```dns
mail._domainkey.example.com. IN TXT "v=DKIM1; h=sha256; k=rsa; p=MIGfMA0..."
```

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

### Execute Post-Initialization Scripts

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/initialization-functions.md

Executes custom initialization scripts located in /docker-init.d/ and /docker-init.db/. Supports sourcing executable .sh files and executing non-executable .sh files with bash.

```bash
execute_post_init_scripts()
```

```bash
# Custom init script at /docker-init.d/my-setup.sh
#!/bin/bash
do_postconf -e "my_custom_param=value"
```

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

### Get Postfix Configuration Parameter Value

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/utility-functions.md

Use `get_postconf` to retrieve the value of a Postfix configuration parameter. It returns the value to stdout and handles cases where the parameter might not exist.

```bash
host=$(get_postconf "myhostname")
echo "Postfix hostname: $host"

size_limit=$(get_postconf "message_size_limit")
if [[ "$size_limit" == "0" ]]; then
  echo "Message size: unlimited"
fi
```

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

### postfix_setup_debugging()

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/postfix-configuration-functions.md

Enables verbose debugging for SMTP connections originating from networks defined in `$POSTFIX_mynetworks`. This function modifies Postfix and OpenDKIM configurations to produce detailed SMTP connection logs when the `INBOUND_DEBUGGING` environment variable is set.

```APIDOC
## postfix_setup_debugging()

### Description
Enables verbose debugging for SMTP connections from specified networks. This function sets up detailed logging for Postfix and OpenDKIM when the `INBOUND_DEBUGGING` environment variable is active.

### Method
Shell Function

### Parameters
#### Environment Variables
- **INBOUND_DEBUGGING** (string) - Optional - Set to any value to enable debugging.

### Behavior
- Sets `debug_peer_list` to the value of `$POSTFIX_mynetworks`.
- Enables `LogWhy yes` in OpenDKIM configuration.
- Produces verbose SMTP connection logs.

### Example
```bash
export INBOUND_DEBUGGING=1
postfix_setup_debugging
# Enables debugging for all trusted networks
```
```

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

### Run Postfix with Authenticated Relay Host

Source: https://github.com/bokysan/docker-postfix/blob/master/README.md

Configure Postfix to use a relay host that requires username and password authentication. Provide credentials using environment variables.

```shell
docker run --rm --name postfix -e RELAYHOST=mail.google.com -e RELAYHOST_USERNAME=hello@gmail.com -e RELAYHOST_PASSWORD=world -p 1587:587 boky/postfix
```

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

### Get DKIM Selector for Domain

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/dkim-functions.md

Parses DKIM selector configuration for a given domain. It checks the DKIM_SELECTOR environment variable for domain-specific mappings and falls back to a default or a system default.

```bash
get_dkim_selector() DOMAIN
```

```bash
export DKIM_SELECTOR="example.com=mail,test.org=dkim,default"

get_dkim_selector "example.com"    # Output: mail
get_dkim_selector "test.org"       # Output: dkim
get_dkim_selector "other.com"      # Output: default
get_dkim_selector "nothing.com"    # Output: default

# Reset selector
unset DKIM_SELECTOR
get_dkim_selector "anything.com"   # Output: mail
```

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

### Apply Custom Postfix Commands

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/postfix-configuration-functions.md

Applies arbitrary Postfix configuration parameters using environment variables. Set environment variables prefixed with POSTFIX_ to configure specific Postfix settings. An empty value deletes the parameter.

```bash
postfix_custom_commands()

```

```bash
export POSTFIX_maximal_queue_lifetime=5d
export POSTFIX_bounce_queue_lifetime=3d
postfix_custom_commands()
# Sets maximal_queue_lifetime and bounce_queue_lifetime

```

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

### Postfix Configuration Functions

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/MANIFEST.txt

Details on 13 functions for configuring Postfix parameters within the Docker image.

```APIDOC
## Postfix Configuration Functions

### Description
Documentation for 13 functions that allow for the configuration of various Postfix parameters.

### Usage
Consult `api-reference/postfix-configuration-functions.md` for a complete list of functions, their parameters, and usage examples.
```

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

### postfix_custom_commands()

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/postfix-configuration-functions.md

Applies arbitrary Postfix configuration parameters dynamically through environment variables. Any environment variable prefixed with `POSTFIX_` will be processed, allowing for flexible configuration adjustments.

```APIDOC
## postfix_custom_commands()

### Description
Applies arbitrary Postfix configuration parameters via environment variables. This function allows users to set or delete Postfix configuration options by defining environment variables prefixed with `POSTFIX_`.

### Method
Shell Function

### Parameters
#### Environment Variables
- **POSTFIX_*** (string) - Optional - Any environment variable starting with `POSTFIX_` will be processed. The prefix `POSTFIX_` is removed to determine the configuration parameter name.

### Behavior
- Iterates through all environment variables starting with `POSTFIX_`.
- Extracts the configuration parameter name by removing the `POSTFIX_` prefix.
- Sets the configuration parameter in Postfix. If the environment variable's value is empty, the parameter is deleted from the Postfix configuration.

### Example
```bash
export POSTFIX_maximal_queue_lifetime=5d
export POSTFIX_bounce_queue_lifetime=3d
postfix_custom_commands
# Sets maximal_queue_lifetime and bounce_queue_lifetime
```
```

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

### Run Docker Postfix for Simple Relay (Gmail)

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/INDEX.md

Use this command to configure the Postfix container to relay emails through Gmail using standard SMTP authentication. Ensure you have an app-specific password for your Gmail account.

```bash
docker run -e ALLOWED_SENDER_DOMAINS="example.com" \
           -e RELAYHOST="smtp.gmail.com:587" \
           -e RELAYHOST_USERNAME="user@gmail.com" \
           -e RELAYHOST_PASSWORD="app-password" \
           -p 1587:587 \
           boky/postfix
```

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

### Run Postfix Container with Mounted DKIM Keys

Source: https://github.com/bokysan/docker-postfix/blob/master/README.md

This command runs the Postfix Docker container, mounting a local directory containing DKIM keys to the container's OpenDKIM key directory. It also specifies allowed sender domains.

```shell
docker run --rm --name postfix -e "ALLOWED_SENDER_DOMAINS=example.com example.org" -v /host/keys:/etc/opendkim/keys -p 1587:587 boky/postfix
```

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

### Run Postfix with Relay Host

Source: https://github.com/bokysan/docker-postfix/blob/master/README.md

Use this command to run the Postfix container and relay all outgoing emails through a specified host. Ensure the container is mapped to the correct port.

```shell
docker run --rm --name postfix -e RELAYHOST=192.168.115.215 -p 1587:587 boky/postfix
```

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

### Run Postfix Container with Docker

Source: https://github.com/bokysan/docker-postfix/blob/master/README.md

Use this command to run the Postfix container with specified environment variables and port mapping. Ensure your outgoing port 25 is not blocked by your ISP.

```shell
docker run --rm --name postfix -e "ALLOWED_SENDER_DOMAINS=example.com" -p 1587:587 boky/postfix
```

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

### Override Postfix Configuration Settings

Source: https://github.com/bokysan/docker-postfix/blob/master/README.md

Any Postfix configuration option can be overridden using POSTFIX_<name> environment variables. For example, POSTFIX_allow_mail_to_commands can be set to control mail delivery commands. An empty variable removes the setting.

```shell
docker run --rm --name postfix -e "POSTFIX_allow_mail_to_commands=alias,forward,include" -p 1587:587 boky/postfix
```

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

### Postfix SMTP Submission Port Authentication Setup

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/authentication-functions.md

Sets up SMTP submission port authentication for client access using SASLDB2. This function creates necessary configuration files and SASL users when the SMTPD_SASL_USERS variable is defined.

```bash
postfix_setup_smtpd_sasl_auth()
```

```bash
export SMTPD_SASL_USERS="user1@example.com:password1,user2@example.com:password2"
postfix_setup_smtpd_sasl_auth
# Creates SASL users for submission port access
```

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

### postfix_upgrade_conf()

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/api-reference/database-upgrade-functions.md

Migrates legacy database references (e.g., `hash:`, `btree:`) in `/etc/postfix/main.cf` to the modern LMDB format. It identifies and regenerates affected database files using `postalias` or `postmap`.

```APIDOC
## postfix_upgrade_conf()

### Description
Migrates legacy database references (e.g., `hash:`, `btree:`) in `/etc/postfix/main.cf` to the modern LMDB format. This function scans the configuration file, replaces old prefixes with `lmdb:`, and regenerates the affected database files using `postalias` or `postmap` as appropriate. It handles multi-line entries, duplicates, and missing files, and continues operation even if some database regenerations fail.

### Function Signature
```bash
postfix_upgrade_conf()
```

### Parameters
None

### Returns
None

### Target File
`/etc/postfix/main.cf`

### Behavior
1. Scans `/etc/postfix/main.cf` for lines containing `hash:` or `btree:` prefixes.
2. Replaces these prefixes with `lmdb:`.
3. Identifies database files that need regeneration based on whether they are alias maps or other map types.
4. Regenerates affected databases using `postalias` (for alias maps) or `postmap` (for other map types).

### Example Configuration Changes

**Before:**
```
virtual_mailbox_maps = hash:/etc/postfix/virtual
transport_maps = btree:/etc/postfix/transport
alias_maps = hash:/etc/postfix/aliases
```

**After:**
```
virtual_mailbox_maps = lmdb:/etc/postfix/virtual
transport_maps = lmdb:/etc/postfix/transport
alias_maps = lmdb:/etc/postfix/aliases
```

### Commands Executed (Examples)
```bash
postmap lmdb:/etc/postfix/virtual  # Regenerate virtual database
postmap lmdb:/etc/postfix/transport # Regenerate transport database
postalias lmdb:/etc/postfix/aliases # Regenerate aliases
```

### Edge Cases Handled
- **Multi-line entries:** Uses `sed` to correctly handle entries that span multiple lines.
- **Duplicates:** Deduplicates database entries before regeneration.
- **Missing files:** Skips regeneration for source files that do not exist.

### Error Handling
- The function continues execution even if individual database regeneration commands fail.
- It does not exit the script on errors related to specific databases.

### Use Cases
- **Migrating from Debian to Alpine:** Addresses the removal of `hash:` support in Alpine.
- **Updating Postfix versions:** Modernizes configurations that use older database types.
- **Persisted configuration volumes:** Fixes incompatible configurations loaded from older image versions.
```

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

### Access Mail Service via NodePort

Source: https://github.com/bokysan/docker-postfix/blob/master/helm/mail/templates/NOTES.txt

Use this snippet to get the NodePort and Node IP to access the mail service when service type is NodePort. It exports variables for the Node Port and Node IP, then prints the access URL.

```bash
{{- if contains "NodePort" .Values.service.type }}
  export NODE_PORT=$(kubectl get --namespace {{ .Release.Namespace }} -o jsonpath="{.spec.ports[0].nodePort}" services {{ include "mail.fullname" . }})
  export NODE_IP=$(kubectl get nodes --namespace {{ .Release.Namespace }} -o jsonpath="{.items[0].status.addresses[0].address}")
  echo http://$NODE_IP:$NODE_PORT
{{- end }}
```

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

### Run Docker Postfix with DKIM and Inbound Auth

Source: https://github.com/bokysan/docker-postfix/blob/master/_autodocs/INDEX.md

Set up the Postfix container with DKIM auto-generation and inbound SMTP authentication using SASL users. This requires mounting volumes for DKIM keys and Postfix spool.

```bash
docker run -e ALLOWED_SENDER_DOMAINS="example.com" \
           -e RELAYHOST="smtp.gmail.com:587" \
           -e RELAYHOST_USERNAME="user@gmail.com" \
           -e RELAYHOST_PASSWORD="password" \
           -e DKIM_AUTOGENERATE=1 \
           -e SMTPD_SASL_USERS="app@example.com:apppass" \
           -v postfix_keys:/etc/opendkim/keys \
           -v postfix_spool:/var/spool/postfix \
           -p 1587:587 \
           boky/postfix
```