ThunderSec also introduces client-side checks for DomainKeys Identified Mail (DKIM) and Sender Policy Framework (SPF) violations.
Whitelists can be used to mark DNSBL, SURBL, DKIM and SPF violations as legitimate for improved efficacy and user experience.
The source code and issue tracker for this extension is hosted at GitHub at the following URL:
https://github.com/itemir/thundersec
The add-on can be found on Mozilla Add-ons page at the following URL:
https://addons.mozilla.org/en-US/thunderbird/addon/thundersec/
ThunderSec installation instructions are available at the following URL:
https://github.com/itemir/thundersec/wiki/ThunderSec-Installation-Instructions