nc unix_listen .test-sock
mda = ./mda-lmtp --addr=.test-sock --addr_network=unix \
-f from -d to < test-email
nc -> 220 Hola desde expect
nc <~ LHLO .*
nc -> 250-Bienvenido!
nc -> 250 Contame...
nc <- MAIL FROM:<from>
nc -> 250 Aja
nc <- RCPT TO:<to>
nc -> 250 Aja
nc <- DATA
nc -> 354 Dale
nc <- Subject: test
nc <-
nc <- This is a test.
nc <- .
nc -> 452 Nananana
mda <- Delivery failed remotely: 452 Nananana
mda wait 75