dkimproxy 1.4.1 SMTP proxy to sign and verify Internet mail with DKIM headers
DKIMproxy is an SMTP proxy that signs and verifies Internet mail using the
Mail::DKIM Perl module. It comprises two separate proxies: an outbound proxy for signing outgoing email, and an inbound proxy for verifying signatures of incoming messages.
It was designed for Postfix, but can be used to add DKIM support to nearly any existing mail server. With Postfix, the proxies can operate as either
After-Queue content filters.