README
¶
loopia-dns-updater
This is a small utility for updating the Loopia DNS records through the Loopia API. It is capable of updating IPv4 A records and IPv6 AAAA records.
I'm using the tool myself and I have tested it, but please, make a backup of your domain before running this utility. Also run a dry run first to check that it behaves as expected.
Design decisions
- Must work with lots of hosts/records behind SLAAC
- Rely on the IP of the interface rather than use an external service to find the IP
- Auto discover of records in need to be updated (idea from one of my brothers)
- Should work with both IPv4 and IPv6
- The use case is home use and small office use with a single FW/Router
- No config or Loopia credicals on every host with IPv6 services
- Should be a small stand-alone binary
Supported operating systems
The build script builds for Linux, FreeBSD and OpenBSD, but it should be possible to compile for other operating systems and CPU architectures.
Execution
The software runs as a single execution. Place it in cron or something similar to run periodically
The util will store the relevant IPs of the interfaces. If they are not updated, the util will not call Loopia to check whether update is needed. To force execution, delete the data directory.
Execution flags
| Flag | Description |
|---|---|
| -c {file} | Config file location. If not set, /etc/loopia-dns-updater.yaml is used |
| -d | Debug output |
| -h | Show help |
| -n | Dry run |
| -q | Quiet. Minimal logging |
| -s | Data directory. A directory where the utility store it's data. If not set, /var/lib/loopia-dns-updater is used. |
Logging
Logging is performed to stdout.
IPv4 handling
The IPv4 addresses are always treated as with netmask /32, i.e. the complete IP of the interface is updated in the DNS.
IPv6 handling
The IPv6 handling supports SLAAC. This is done by reading the netmask of the interface. The prefix (most often the upper 64 bits) is replaced in the AAAA record. The lower part (most often the lower 64 bits) is kept as is. This method also works for /128 addresses where the full address is replaced as with IPv4.
Configuration file
A sample file is provided below
domains:
- name: example.com
interfaces:
- ifName: vio1
matchUnknown4: true
match4:
- ssh.example.com
match6:
- ssh.example.com
- ifName: vio5
matchUnknown6: true
loopia:
username: username-from-loopia-api
password: password-of-loopia-api-user
Configuration items:
| Item | Description |
|---|---|
| domains | List of domains to update |
| domains.name | FQDN of the domain |
| domains.interfaces | List of interfaces where to find IP for the domain |
| domains.interfaces.ifName | The interface name |
| domains.interfaces.match4 | List of FQDN that should be assigned the IPv4 of the interface |
| domains.interfaces.match6 | List of FQDN that should be assigned the IPv6 of the interface |
| domains.interfaces.matchUnknown4 | Update A records that are not listed in any {this}.interfaces.match4 with the IPv4 of this interface |
| domains.interfaces.matchUnknown6 | Update AAAA records that are not listed in any {this}.interfaces.match6 with the IPv6 of this interface |
| loopia.username | Loopia API user. The user will call GetSubdomains, GetZoneRecords and UpdateZoneRecord |
| loopia.password | Loopia API password |
| executeOnChange | Command to execute if the relevant IPs are changed |
Directories