Re: [exim] Exim server behind NAT router (and HELO)

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Autor: Richard Clayton
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A: David Brodbeck
CC: exim
Assumpte: Re: [exim] Exim server behind NAT router (and HELO)
In message <C823AC1DB499D511BB7C00B0D0F0574CC40FF2@???
lean.com>, David Brodbeck <DavidB@???> writes

>> -----Original Message-----
>> From: Richard Clayton [mailto:richard@highwayman.com]
>
>> large sites (millions of emails a day, hundreds of
>> thousands of customers) would drop too much legitimate email by being
>> overly pedantic about HELO strings.
>
>I don't even run a large site and I can't afford it. A fair number of
>customers and vendors we deal with regularly seem to HELO with names like
>"foobar.local" for some reason.


they're almost certainly running a copy of Exchange... quite a lot of
these sites go

        MAIL FROM: <somethingorother.local>


as well... in fact I have a collection of 155 of this type of
misconfiguration to hand from a medium-sized ISP's customers one recent
weekday (that's 155 customers, not 155 emails) ...

67 of these have a sender ending in ".local" and another 31 had
something@ONE_WORD_IN_CAPS... and, lest people get snooty, I can see
other dumbness clearly from non-Windows machines.

viz: these people never see any bounce messages; it must be a whole
different world for them :)

>HELO strings containing an underscore
>aren't uncommon here, either.


last time I looked, over half of customer email to the smarthost (which
of course exists so that this sort of thing doesn't matter) said HELO
with a single word... even Bayes will struggle with that :)

- -- 
richard                                              Richard Clayton


They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety.         Benjamin Franklin