[Raw Msg Headers][Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
SMTP "TURNME"
Hello,
Due to some need, I decided to do an attempt at creating
a safe way to enable user to initiate scheduling to any
target system.
The RFC-821 defines a "TURN" command, however:
- it has not been defined adequately -- how it knows which
host is in the question ? From HELO argument ?
- it is widely considered a security hole - or very least
privacy invasion, and thus it has not been implemented
(One can rob email targeted to other systems with it.)
As the scheduler attempts to send email out, it may get
a (connection) timeout at some point, and thus be forced
to retry, and the retries have backoff..
Now enter a dialup user, who wants to minimize the time
at the connection, and still get email via SMTP. Thus
this user needs a way to "kick" the scheduler to do an
early retry, and not wait for 2-6 hours:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TURNME mea.cc.utu.fi
250-A TURNME request is initiated - lets hope the system
250-has resources to honour it. We call the remote, if
250 we have anything to send there.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
It does not interact with the scheduler to know, if this
target system has anything in the queue; thus the "canned"
message.
The argument to TURNME is target system HOST string
as used by the scheduler. Especially it does NOT pay
any attention to the CHANNEL specifier. All threads
with this HOST-string are kicked immediately.
(Consider: local/aabbcc vs. uucp/aabbcc)
(It is used in case insensitive manner, though.)
You can test the feel of it at nic.funet.fi's SMTP-server,
and get it at next source dump; somewhen..
/Matti Aarnio <mea@nic.funet.fi>