DKIM Proxy is a reference implementation of the RFC 4871 (DomainKeys Identified Mail – DKIM) standard. This implementation can be deployed as a proxy in front of a SMTP or POP3/IMAP4 server.
The DKIM standard and the provided implementation facilitate the integration of appropriate means to reliably authenticate sender domains in e-mail transmissions. DKIM Proxy enables an SMTP server to sign sent e-mails according to the DKIM standard, and POP3 or IMAP4 servers to verify DKIM signatures of received e-mails.
Received e-mails are extended with an additional header field to indicate the result of the signature-verification process. This way, local e-mail clients can be configures to automatically classify incoming e-mails and to identify e-mails originating from invalid sender domains.