''
; ------------------ mail: ${n} ---------------------------
${n} IN MX 10 mail.${conf.name}.
- ;${n} IN MX 50 mx-1.${conf.name}.
+ ${n} IN MX 50 mx-1.${conf.name}.
; https://tools.ietf.org/html/rfc6186
_submission._tcp${suffix} SRV 0 1 587 smtp.immae.eu.