I don't see how it's specific to sending from thunderbird. It's a general issue if you want to use a domain for mailing.

It's not spesific to the mua, no. But as thread starter (ed: first responder) said:

> Word of advice for anybody doing this: make sure you have a way to SEND email using one of your aliased addresses

So a) you need a mua like thunderbird that let's you set FROM header - and b) your domain need to be setup to allow your smtp server(s) to send from your domain (sfp).