Is there a way to get the DHCP server to stop handing out my local DNS Suffix. I do not have it set so I assume its inherited but there is an application that I cannot use on my network because it's appending the local DNS Suffix.
There's not really a way to do that completely.
You can disable DHCP lease registration from settings, but your devices will always have that unique name with domain suffix they are a part of.
Unless you change the domain or assign IPs manually on every computers settings, they will always be part of domain of which your opnsense is.
Bummer. I found a work around to rewrite the URL in the meantime.