No, there's no perfect solution for dealing with those broken MTAs. One
of the reason we chose to check for the bad terminator after timeout
was, if we didn't, the message would sit around in the other end's
queue, blocking other messages from flowing. This happened enough times
and we got enough complaints that we made this compromise. Our job was
to get the messages through, not interpreting was inside them. So the
fact that the receiving MUA might have difficulty was less of a concern
to us. Besides, if you get the data through, at least the end user has a
chance of seeing the data. If they don't get the mail, they have no
chance whatsoever. You have to make your choices; your decisions may be
different that ours were.
Tony Hansen
tony(_at_)att(_dot_)com
Paul Smith wrote:
...
I don't see that there's a 'perfect' solution to this, except for everyone
doing everything totally according to the standards, and I don't think
that'll ever happen...
Checking for a CR.CR as the last data received at the point of a timeout is
a possibility, but as I've said it will stop any 'intelligent' MUA
behaviour such as MIME decoding/recoding on messages containing CR line
terminators.
If you always check for CRLF as the message terminator except at a timeout,
but allow any line terminator in the body of a message, then, as well as
introducing complexity, it means that message data may be 'corrupted' if
there are bare CRs or LFs in the middle of a message.
Maybe the best thing to do is just to disobey the 'be flexible in what you
receive' idea, and just reject anything which has incorrect line
terminators - at least that might put pressure on people to use the proper
ones... :-)
Paul VPOP3 - Internet Email Server/Gateway
paul(_at_)pscs(_dot_)co(_dot_)uk http://www.pscs.co.uk/