Re: all major US carriers received text messages overnight that appear to have been sent around Valentine's Day 2019

["Mark Delany" <k3f () november emu st>]

> What I've seen happen more often than that:
>
> Server goes partly belly-up, queue fills up.  Backup process runs, backing up the
> queue. (Optionally here: Reboot the server and lose the queue).  Much later, the
> server hits another issue that requires recovering from backups - and they restore
> a truly ancient copy.

Particularly as mail servers tend to check for expired messages
*after* a delivery attempt. This means a restored queue containing
ancient messages will most likely be given one last delivery attempt
prior to bouncing. One real example comes from the qmail-send man
page:

       queuelifetime
            Number of seconds a message can stay in the queue.  Default:
            604800 (one week).  After this time expires, qmail-send will try
            the message once more, but it will treat any temporary delivery
            failures as permanent failures.

Combine that with the fact that it's not unheard of for SMS servers to
be derived from mail servers (since they do virtually the same thing)
and an accidental queue restore or server revivication seems the most
plausible.


Mark.