If an MTA receives an email that exceeds the message size limit, which bevaviour is preferred? What is the default for common mail servers?
- Reject the email during the SMTP session. The delivering MTA must send a bounce message to the original sender.
- Accept the mail and send a bounce message to the original sender immediately.
- Accept the mail and send a bounce message to the original sender after a timeout.
I've seen a server do 3. and wait for 5 days before sending the bounce. It seems to me this behavior does not make sense as the message size limit is not likely to change often. Should an exceeded message size limit not be immediately regarded as a permanent error?