Unifi DDNS with Route53

Introduction

Unifi network devices support DDNS for a lot of common providers. Unfortunately, route53 is not one of the out of the box supported providers. They do however support the ability to specify custom providers thanks to their use of inadyn. This repo sets up an AWS Lambda fronted by an API gateway that updates a dns record specified in the configuration when it receives updates from your UniFi device.

AWS Setup

First, run the terraform in the terraform directory as a module. The call to this module will look similar to the below example:

module "ddns" {
  source = "git@github.com:nckslvrmn/unifi_ddns_route53/terraform"

  hosted_zone_id = aws_route53_zone.public.zone_id
  domain_name    = "ddns.domain"
  acm_arn        = data.aws_acm_certificate.wildcard.arn
}

The only three inputs needed are:

Name	Value
hosted_zone_id	the hosted zone id of the route53 dns zone to which you intend on publishing the DDNS record
domain_name	the name of the DNS entry in that zone that will point to the API gateway receiving updates
acm_arn	the ARN of an ACM record that validates the DNS for domain_name

Once the terraform is run, you will need to change the value of the ssm parameter and update the lambdas source code. To do this, follow these steps:

1. run aws ssm put-parameter --name "/unifi_ddns_route53_credentials" --value "USERNAME:PASSWORD" --type SecureString --overwrite. This assumes your AWS permissions are set up properly for CLI use. Change the USERNAME:PASSWORD to values you want to use for authenticating this API. These will be used lated in the unifi setup.
2. run cd lambda; zip function.zip lambda.py; aws lambda update-function-code --zip-file fileb://function.zip --function-name ddns. This will place the code in the lambda and deploy it.

UniFi Setup

On the UniFi side, you will have to enable Dynamic DNS. Under Settings, in the advanced section of the Internet configuration for your WAN, you will see the option for Dynamic DNS. Configuration has a few sections and should look like this:

the configuration options are as follows:

Name	Value
Service	set to custom
Hostname	set to the DNS record you want the API to update with your WAN IP
Username	set to the username you specified in the AWS SSM Parameter
Password	set to the password you specified in the AWS SSM Parameter
Server	set to the DNS name of the domain_name value set in the terraform module, with this URI on the end of it /nic/update?hostname=%h&myip=%i. Do not include https://

If you have ssh enabled on your UniFi device, you can confirm these settings have been stored by reading the /run/ddns-eth8-inadyn.conf file. You may also want to run /usr/sbin/inadyn --force -n -C -1 -l debug -f /run/ddns-eth8-inadyn.conf to confirm your settings are correct.

Conclusion

Once the above has been completed, your UniFi device should now send your API the updated IP of your home WAN, and the Lambda will update its corresponding DNS record. You may then use that A record as the target of other CNAMEs, or however else you'd like.