From: Jim Youll <jim(_at_)media(_dot_)mit(_dot_)edu>
...
If there's a relatively very small number of hosts that must do some
protocol (UUCP) and if support for that protocol is holding up other things,
then it would seem to make sense to provide those hosts with a gateway option
that makes their world look just like it did before.
...
For the general case of replacing one messaging protocol with another,
gateways are not just a good idea, but necessary. I am not talking
about the necessity of gateways. SMTP-UUCP gateways can be considered
classic examples of temporary gateways that always seem to last forever.
Instead I'm talking about bounces. Assume you are on the new protocol
side of a gateway between the new, bounce-free, neo-SMTP Internet and
you want to send a message to a user on the old network. The gateway
knows all valid UUCP (or whatever) addresses and so generates appropriate
neo-SMTP errors when presented with a bogus address. (Never mind that
this is obviously grossly impractical.) Thus, the gateway does not
generate bounces for most "spammer joe jobs."
Now consider these cases:
1. between the time the gateway accepts your message and it is
delivered to the distant mailbox, a host name is changed. The
change makes your original address invalid.
2. the UUCP path between the gateway and the distant mailbox is ill
and does not come up for more than 4 days.
3. your message reaches the distant mailbox, but it turns out that
the mailbox is too full and your message is rejected.
4. your message reaches the distant mailbox, but is rejected by a
spam filter.
Would you want some indication of any of those failures?
If so, how would that failur indication differ from a classic SMTP
bounce as far as your MUA is concerned?
Vernon Schryver vjs(_at_)rhyolite(_dot_)com
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