Re: [exim] TLS errors on SMTP (non-AUTH) connections

Vincent Danen wrote:
> * Vincent Danen <vdanen@???> [2007-02-01 11:49:06 -0700]:
>
>>>>> Can you tell what MTA they are using?
>>>> Yeah, they're using exim 4.63 (I'm using 4.5x). I thought it would be a
>>>> sender-verification request too, but that doesn't explain why it worked
>>>> with the telnet "test" but fails when my exim talks to theirs.
>>>>
>>>>
>>> Timing, perhaps?
>>>
>>> Ex: - if you have banner delay and they have a callout timeout that is hte same
>>> - or shorter, what with setup and link turnaround times..
>> I'm thinking this is it. But it doesn't look like they're doing sender
>> verification at all.
>>
>> I read the "RCPT delays and PIPELINING" thread with much interest after
>> I wrote my last message on this where it seems that pipelining is being
>> the culprit here. I have no idea how their server is setup, but seems
>> like there are some delays there that interfere with pipelining (as I
>> did a manual esmtp connection, no STARTTLS, no PIPELINING, and it was
>> delivered).
>>
>> So, the question is, can I disable pipelining for one particular host
>> (in the current exim)? Or disable pipelining for outbound mail
>> altogether?
>>
>> I've got to read the manual on that one. I've never had to think about
>> pipelining before.
>
> Looks like I might have to wait for the new version of exim to do this.
> I set:
>
> pipelining_advertise_hosts = 127.0.0.1
> smtp_enforce_sync = true
>
> but on outgoing connections if the remote advertises pipelining, seems
> like exim will use it no matter what I want.
>
> Sucks, but looks like there isn't a whole lot I can do about this at the
> moment, which is unfortunate. Well, I could use a snapshot I guess but
> that doesn't sound like much of a good idea for a production system.
>
> Thanks for all the tips/pointers and such, but I think until the new
> exim comes out, there isn't much I can do here.
>
> Unless someone else has some creative magic for me to try, of course.
> =)
>
>

Try this first - just for experiment's sake:

pipelining_advertise_hosts = : (the empty list)

That said ISTR that, as you said, Exim *will* use pipelining if the far-end
offers it.

Probably simple enough to disable the very *detection* of that if modifying
source, i.e. - just make Exim 'blind' to the offer.

But I don't see any gain. And I really don't think pipelining per se is the
culprit in your original problem.

The only reason we muck about with it *at all* is that it thumps enough spambots
to be worth whatever modest b/w efficiency loss we suffer. And, of course, we do
use delays here and there for some traffic.

Given that over 90% of our arrivals are single-recipient messages in any case,
and that we have a number of local and remote lookups and such taking up time,
the more efficient *packet* is just not a big deal here.

High-traffic sites would, of course disagree.

JM2CW,

Bill