From ff48f7b016646baa5424272d845a9c0bcf80eefc Mon Sep 17 00:00:00 2001
From: Thomas Oettli <spacefreak@noop.ch>
Date: Fri, 23 Jan 2026 02:02:53 +0100
Subject: [PATCH] Change README.md

---
 README.md | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 64 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index cb566b9..682fda1 100644
--- a/README.md
+++ b/README.md
@@ -198,6 +198,7 @@ notify_change = []
 | ipv6 (IPv6 address) | myip6, ipv6, ip6 |
 | username | username, user |
 | password | password, pass, token |
+| notify_change | notify_change |
 
 ## CLI Usage
 
@@ -280,7 +281,7 @@ ddns-service --daemon --debug
 ### Request
 
 ```
-GET /update?hostname=mypc.dyn.example.com[&myip=1.2.3.4][&myip6=2001:db8::1]
+GET /update?hostname=mypc.dyn.example.com[&myip=1.2.3.4][&myip6=2001:db8::1][&notify_change=1]
 Authorization: Basic base64(username:password)
 ```
 
@@ -289,6 +290,8 @@ Authentication can also be provided as query parameters:
 GET /update?hostname=mypc.dyn.example.com&username=myuser&password=secret
 ```
 
+Set `notify_change=1` to receive an email notification when the IP address changes. Requires email to be enabled and a change notification template configured.
+
 ### IP Detection
 
 - If `myip` and/or `myip6` provided: use those values
@@ -324,6 +327,11 @@ With explicit IP:
 curl -u "username:password" "https://ddns.example.com/update?hostname=mypc.dyn.example.com&myip=1.2.3.4"
 ```
 
+With change notification:
+```bash
+curl -u "username:password" "https://ddns.example.com/update?hostname=mypc.dyn.example.com&notify_change=1"
+```
+
 ### wget
 
 ```bash
@@ -352,9 +360,63 @@ Set `expiry_ttl = 0` to disable expiration entirely for a hostname.
 
 When a hostname expires:
 1. DNS records (A and/or AAAA) are deleted
-2. Email notification is sent to the user
+2. Email notification is sent to the user (if configured)
 3. Records can be restored by sending a new update request
 
+## Email Notifications
+
+Two types of email notifications are supported:
+
+- **Change notifications**: Sent when IP address changes, if client includes `notify_change=1` parameter
+- **Expiry notifications**: Sent automatically when hostname expires due to inactivity
+
+### Configuration
+
+Enable email and configure templates in `[email]` section:
+
+```toml
+[email]
+enabled = true
+smtp_host = "localhost"
+from_address = "ddns@example.com"
+change_notification_template = "/etc/ddns-service/change_notification.j2"
+expiry_notification_template = "/etc/ddns-service/expiry_notification.j2"
+```
+
+Example templates are provided in the `files/` directory.
+
+### Template Variables
+
+Templates use Jinja2 syntax. Available variables:
+
+**Change notification:**
+| Variable | Description |
+|----------|-------------|
+| hostname | Hostname (without zone) |
+| zone | DNS zone |
+| fqdn | FQDN (hostname.zone) |
+| ipv4_changed | Boolean, IPv4 changed |
+| ipv4 | Current IPv4 address |
+| last_ipv4_update | Last IPv4 update time |
+| ipv6_changed | Boolean, IPv6 changed |
+| ipv6 | Current IPv6 address |
+| last_ipv6_update | Last IPv6 update time |
+| expiry_ttl | Expiry TTL in seconds |
+
+**Expiry notification:**
+| Variable | Description |
+|----------|-------------|
+| hostname | Hostname (without zone) |
+| zone | DNS zone |
+| fqdn | FQDN (hostname.zone) |
+| ipv4_expired | Boolean, IPv4 expired |
+| last_ipv4 | Last IPv4 address |
+| last_ipv4_update | Last IPv4 update time |
+| ipv6_expired | Boolean, IPv6 expired |
+| last_ipv6 | Last IPv6 address |
+| last_ipv6_update | Last IPv6 update time |
+| expiry_ttl | Expiry TTL in seconds |
+
 ## Logging
 
 The daemon supports stdout, syslog, and file logging targets.