Hello... I just figured out how to keep my outgoing e-mail compliant to the Sender Policy Framework (SPF) protocol after receiving "bounce" messages from some of my recipients... The fix to this required nothing in the setup of Thunderbird and instead required a "TXT" record to be added to my domain's registration site... In researching the SPF, I stumbled upon yet another authentication system called Domain Keys Identified Mail (DKIM)... The description of this protocol seems to indicate an SMTP-proxy needs to be setup to sign (on the sending side) and verify (on the receiving side) messages that are compliant to this authentication strategy... I found an add-on to Thunderbird that authenticates DKIM on the receiving side... My question is... Is the DKIM Proxy, as mentioned in the DKIM proxy websites (http://dkimproxy.sourceforge.net/), something that is an add-on to Thunderbird to digitally sign the outgoing e-mail? If so... Is there an add-on to implement the DKIM authentication? Thank you! Rick Herrick