Sendmail 8.9.0 (currently in beta test) supports a local configuration option
to limit the maximum number of RCPT TOs as documented thusly:
[infinite] If set, allow no more than
the specified number of recipients in
an SMTP envelope. Further recipients
receive a 452 error code (i.e., they
are deferred for the next delivery
Does anybody see a need/desire/etc for an ESMTP option to advertise
this limit, so the upstream end can avoid sending a RCPT TO: that
will just get 452'd anyhow?
Straw man proposal:
250-MAXRECIP nnn to state that more than nnn receipts will not be accepted.
Computer Systems Senior Engineer