Comodo DNS on Firefox

Comodo Secure DNS - DNS Help - DNS
1

I need to use comodo dns on Firefox, but DIRECTLY on Firefox, because I cannot change settings of network card.
Is it possible? Is there a Firefox extension that allows this?

2
I need to use comodo dns on Firefox, but DIRECTLY on Firefox, because I cannot change settings of network card.
Thats going to be a problem because Mozilla Firefox uses the dns used by the operating system.
3

Yes, all browsers use by default dns by OS. But is there an extension for Firefox in which I can choose DNS? And if today there is not, can I ask to a developer to build it or is it impossible?
Mod edit: Added quote tags, Captainsticks.