I think the simplest way of dealing with messages in flight across mail transport agent changes would be to define a simple queue structure to hold the messages across mta installations.
Probably the simplest mechanism is a directory with one file per message, first line being envelope from address, subsequent line(s) being destination address(es), then a blank line, then the message (headers and all). Policy should be that a mail transport agent postrm should move any undelivered mail messages into this queue with this format and that the postinst should move messages from this queue to the new mta's queue. ssmtp would require special effort (either refuse to install using a check in preinst or a queue run job which checks the error code from /usr/sbin/sendmail). An mta shouldn't be considered installed until all messages have been succefully moved out of this temporary queue (technically, it's ok if unreasonable messages get bounced, and this should be considered a success). Comments? -- Raul -- E-mail the word "unsubscribe" to [EMAIL PROTECTED] TO UNSUBSCRIBE FROM THIS MAILING LIST. Trouble? E-mail to [EMAIL PROTECTED] .
