What software has to change, to use DKIM?
The signer needs to add code in the appropriate agent, to perform signing, and they need to modify their DNS administrative tools to permit creation of DKIM key records. A validator needs to add code to the appropriate agent and then feed the result into the portion of their system needing it, such as a filtering engine. The mere existence of a valid signature does not imply that the mail is acceptable, such as for delivery. Acceptability requires an assessment phase. Hence the result of signature validation must be fed into a vetting mechanism that is part of the validator’s filter.
