HOW TO:
In order to let users set up their reversedns it is required a valid ungleich account, you can register at https://account.ungleich.ch/register/
After the registration, you need a valid otp account and seed, to do this you can submit a request with curl with the following parameters
curl -d '{"username":"your_ungleich_username", "password":"********", "realm": "ungleich-user"}' -H "Content-Type: application/json" -X POST https://account.ungleich.ch/otp/
And it will retrieve a seed (a code that you can set up in any otp app in order to generate your 6 digits otp token)
After this, you are now ready to set up your reversedns
Clone ungleich-cli and inside the folder type
python ungleich dns --set-reverse <yourvmipaddress> --user <ungleich_username> --token <otp_token> --realm ungleich-user --email <youremail> --name mirror.example.com
If the request is successful it will return a 200 response with the reversed ip address
or it would return an authentication failed message, in case the vm-ip-username-token combination is wrong.