ENMA is a milter program for the domain authentication technologies.
It authenticates sender's address with SPF and Sender ID, then
labels the result onto the Authentication-Results: field.

ENMA implements the following RFCs and an Internet Draft:

- RFC4406 (Sender ID)
- RFC4407 (PRA)
- RFC4408 (SPF)
- draft-kucherawy-sender-auth-header-15
  (the Authentication-Results: field)

ENMA is developed by IIJ. IIJ has been using several domain
authentication software, though, all of them appeared unstable. ENMA
is designed and implemented in order to stand large ISP's operation
and is well-tested.