RE: HELO/EHLO Check Processing Limits (was: New draft (was: query format

> -----Original Message-----
> From: owner-spf-discuss(_at_)v2(_dot_)listbox(_dot_)com
> [mailto:owner-spf-discuss(_at_)v2(_dot_)listbox(_dot_)com]On Behalf Of Frank 
> Ellermann
> Sent: Friday, March 25, 2005 9:13 AM
> To: spf-discuss(_at_)v2(_dot_)listbox(_dot_)com
> Subject: [spf-discuss] New draft (was: query format, load, and stunt
> servers, oh my)
>
>
> Andy Bakun wrote:
>
> > > I raise this question now, because it will be a lot easier
> > > to modify the standard now than later.
> > Is this actually true?  Can we get this verified?  What kinds
> > of changes can be made to the spec at this point?  I thought
> > someone had said effectively "not many".
> Anything which doesn't break valid policies is not completely
> off limits.  If some old implementations are more liberal than
> the actual standard says it's also tolerable.  Otherwise it's
> v=spf2 or spf2.0.  For spf2.0 it must not break Sender-ID, and
> it should include positional modifiers.  For v=spf2 it can be
> anything.
>
> Things planned for draft -01:  Remove "zone cut" everywhere.
> Replace "MAY check HELO" by "SHOULD check HELO".  Add a proper
> IANA template for the Received-SPF header field.
>
>                      Bye, Frank
This reminds me, previously we discussed the idea that the results for
HELO/EHLO ought perhaps to be treated differently, because there really was
no reason for a valid NEUTRAL reponse for HELO/EHLO.

I am wondering similarly, if HELO/EHLO should have different processing
limits?

The most common record encountered during HELO/EHLO checks is "v=spf1
a -all".  Unless some is using the same HELO/EHLO for all their mail servers
(as, IIRC, Hotmail), there should be no need for a more complex record than
that.

Part of the reason that I'm think the limit should be smaller is that even
if an MTA only accepts connections that wait for server response, it would
be much less expensive to trigger a response at HELO/EHLO that it would
based on MAIL FROM: (which might not trigger until after RCPT TO:).

Scott Kitterman