Re: [exim4] Testing and making sense of smtp output
Joe <joe@jretrading.com> writes:
> On Sat, 18 Oct 2014 00:13:54 +0100
> Brian <ad44@cityscape.co.uk> wrote:
>
>> On Fri 17 Oct 2014 at 03:20:44 +0200, lee wrote:
>>
>> > Brian <ad44@cityscape.co.uk> writes:
>> >
>> > > Not that I'm suggesting setting up exim to offer an invalid HELO;
>> > > it will lead to trouble sooner or later. However, as a reason for
>> > > mail being rejected or not arriving it doesn't come top of the
>> > > list.
>> >
>> > Not accepting invalid HELOs is pretty high on the list because it's
>> > a very simple check. It gets rid of quite a lot of spam with
>> > minimal resource usage.
>>
>> It could also get rid of a lot of legitimate mail because of
>> misconfigured clients. ISPs get flack doing that so they come
>> to a decision whether it is worth being so strict. Many ignore
>> invalid HELOs.
>>
>>
>
> [...]
>
> A public-facing SMTP server, accepting arbitrary unauthenticated email
> needs to be a bit more picky, and if a network MTA has an invalid HELO,
> someone should be told to fix it fairly quickly.
Exactly --- unfortunately, it isn't always possible.
Don't give up on telling people how they need to fix their MTAs,
though.
Besides, I cannot seriously accept mail from an MTA which is
misconfigured even in the most basic things because I can not assume
any responsibility that I will be able to correctly handle the mail
coming from or going to it. It's just another misconfigured MTA, and
I would have to be crazy to misconfigure mine to accomodate other
peoples misconfigurations.
When you start doing that, it won't take long before email delivery
will stop working altogether.
--
Again we must be afraid of speaking of daemons for fear that daemons
might swallow us. Finally, this fear has become reasonable.
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