This is really only practical for MSAs. Special purpose clients should not be talking directly to other people’s MTAs in this day and age. Eliot > On Dec 23, 2019, at 00:34, Viktor Dukhovni <ietf-dane@xxxxxxxxxxxx> wrote: > > Address literals remain a valid part of the SMTP protocol, useful > between minimal SMTP clients (special-purpose appliances of various > sorts, and some MUAs) and their configured SMTP relays (smarthosts).
