[Top] [All Lists]

Re: Multi-Line Greetings A Certainty?

2010-02-15 17:35:59

Sabahattin Gucukoglu wrote:

On 15 Feb 2010, at 05:30, Hector Santos wrote:
Sabahattin Gucukoglu wrote:
I imagine it's more of an implementation robustness issue to support multiline greetings 
given the current text of RFC 5321.  However, Postfix's new postscreen daemon, docs , seems to be relying on it to do its job.  Also 
does something else disturbing (in typical Postfix experimental fashion) which is to 
disconnect clients just for not liking the initial "Teaser" banner.  According 
to the STANDARDS section, this is RFC 5321-stipulated stuff.  According to my experience, 
yeah, probably works for short enough timeouts, and I've seen plenty multiline greetings 
in the wild ...
I don't like spam either, but does this not strike others as being really quite 
dangerous thinking and uncertain games to be playing?
Only the good guys complain when are problems, not bad guys.

Yes.  That's because we have more scruples than spammers.  It's a good point in 
irony, though. :-)

In my opinion, one of the strongest defense against spam is enforcing or 
mandating SMTP compliance.  Once you relax, it invites problem and uncertainty.

That is true, with the understanding that (a) spammers can and do catch up with the 
advancement of any threat to their techniques and (b) unfortunately, not all "Good 
guys" are indistinguishable from spammers themselves, leading to conservatism that 
is regrettably necessary.  This latter is particularly true when the author of the 
non-compliance has no justification to fix their broken implementations, usually because 
it has no business need (as compared to falling out with the conforming world).  Just to 
pick any old example, I can't write an MTA that doesn't accept spaces on either side of 
the brackets, in perfect conformance with RFC 5321 and with implementation benefits to 
myself, otherwise a very, very popular desktop application will not work with it, and *I* 
will be wrong, to blame, and lose business and/or mindshare.

True that.  Like, I recall the OE  issue there. :)

So let me change my badly paraphrase of an old saying:

    "What is good for AOL and Microsoft, is good for Email!"

Basically, it appears in both cases, people had to accept because the really tall boys were doing something different than most and if you didn't accept it, you would lose business (and mindshare).

  OE issues a MAIL FROM:<space>      <- Your receiver supported it.
  AOL issues extended welcome lines  <- Your client supported it.

Personally, the space issue a was very minor "innocent" oops, compared to a very fundamental multi-line support issue. It would be really nuts if servers had to turn off multi-line responses, not just the welcome but at each state, specially RCPT TO:, just because there *might* be one or more MTAs out there who didn't support it. I don't think any legit MTA can afford not to support it.

As mentioned in another post, we had ours OFF until AOL did it, and then turned it on by default. I only recall two very early reports (2003/4 time frame?) from SMTP customers, if I recall, one had some user with an old FTP TO EMAIL gateway hub tool, TRANSACT?, the author fixed it, and the other was the old PHP mail command (internal or 3rd party script) which was quickly fixed or replaced once highlighted by the operator who was using it in some web mail form thing. I have not heard any "good guys" complain since then. If so, and it was a constant issue, no doubt, it would be turned off in the default setup.


Hector Santos

<Prev in Thread] Current Thread [Next in Thread>