Hi,

Thank you, at this time the block list is pulled from a list maintained by another party. However, if you have a proxy you can list the sites blocked there. There are some exceptions list that block websites from certain actions that you can block in the options/preferences of Firefox.

Also, there are some add ons that do this as well Blocksite

Hope this helps.

Check this article for more information on blocking a sender.

Blocking a sender

There is no such thing as a whitelist in Thunderbird, however, adding contacts into your address book will prevent them from being classified as spam.

Junk Mail Controls