SMTP was designed around the assumption that nodes could go down or network partitions could happen. If you are unreachable, the mail server that is trying to

SMTP was designed around the assumption that nodes could go down or network partitions could happen. If you are unreachable, the mail server that is trying to contact you should try again later. How many times, at what interval and for how long retries happen vary. Most servers will notify the sender saying that “message delivery failed permanently” if the receiver is unreachable for such a long period of time that the sender server gives up. So between the resilience to temporary unreachability and the fact that the sender should be notified if delivery times out, I would say that the chance that anything important is lost is very slim. The bigger problem is the fact that home ISPs often block outbound SMTP, as well as the fact that their IP blocks are often regarded as low trust by others, meaning that you will certainly run into problems sending mail every now and then. I did not yet read the OP link, but am going to, so I don’t know if they offer proxying/forwarding of outbound SMTP.