DKIMproxy is an SMTP-proxy that signs and/or verifies emails, using the Mail::DKIM module. It is designed for Postfix, but should work with any mail server. It comprises two separate proxies, an "outbound" proxy for signing outgoing email, and an "inbound" proxy for verifying signatures of incoming email (administrators can decide if they want to run both, or only one of them). With Postfix, the proxies can operate as either Before-Queue or After-Queue content filters, and they also can be chained with content filter proxies like Amavis, which is the current default configuration of the package.