Can dnsomatics update dynu?

Yes. DNSOmatic supports Dynu dynamic DNS service.

I keep getting a bad auth error. All values i use in dnsomatic are the same values to login to dynu.com. What needs to be done to auth?

to make sure your settings are correct. Your username is ''.

What IP update client software are you using? To use DNSOmatic with Dynu, you need to do the following:

1. Go to DNS-O-Matic and add a service. Select 'dynu' from the service provider dropdown list. Enter your Dynu username and password and the hostname you have with Dynu and save the service.

2. Download an IP update client such as Mars Updater for Windows. Use the following:

Username: your DNS-O-Matic username
Password: your DNS-O-Matic username
Hostname: your Dynu hostname
DNS Service Provider: DNS-O-Matic.com

Or you can simply use Dynu IP Update client and not go through DNS-O-Matic.

I am seeing exactly the same issue. Dns-o-matic reports "badauth" for Dynu service. I tried both login password as well as the "IP Update Password". I am updating from Tomato firmware, but that is going through fine, the auth error is seen on the Dns-o-matic side. Any help is appreciated.

Are you using DNS Omatic username and password in Tomato firmware?