[ On Thursday, June 30, 2005 at 05:47:09 (+0100), Mark Smith wrote: ]
> Subject: RE: [exim] a large number of domains fronted by Exim are refusingbounces...
>
> Where did this idea start that Exim on cPanel systems doesn't accept null
> senders? It does, and always has done.
Because that's the way it seems to be, given the evidence so far.
I've now encountered three rather large hosting providers that use
cPanel and Exim and which refuse empty sender addresses.
One of them barely knew they were using Exim. They certainly had not
done any customization to their Exim config nor would they admit to
having made any changes to cPanel.
One of them knew cPanel generated their Exim config and they didn't want
to mess with it (and didn't know of any template they could modify).
They also thought they had found a feature in cPanel that would allow
them to whitelist null sender addresses, but it turned out they were
confused about what the "sender address" was and what the "recipient
address" was, and they were whitelisting the latter to allow empty
recipient addresses (though I didn't test to see what the effect on the
recipient address was).
The other one had chosen to configure cPanel and/or Exim to reject null
senders and admitted as much, but only after trying to pretend (with a
lame transcript of an incomplete test session) that they were not
blocking null senders.
Perhaps the first two just suffered from the "help" of whomever they
hired to install cPanel for them.
In any case the fault is not that of cPanel or its users -- the fault
lies squarely on Exim which makes it so easy for these people, i.e.
those building and/or installing cPanel, to break SMTP error handling.
Clearly this discussion has revealed that many people do indeed wish to
be idiots about unilaterally blocking null sender addresses, or even to
be slothful about selectively blocking null sender addresses based on
irrelevant unrelated criteria and because they're too lazy or unwilling
to properly identify junk and junk sources regardless of what sender
address it arrives with. This discussion has also demonstrated that
those people like Exim because it is the MTA which makes it very easy
for them to do this kind of braindamage to SMTP.
My goal was to raise the issue of why Exim was allowing these people to
get away with this kind of abuse of SMTP error handling, but I didn't
expect quite so many Exim users to defend it so vigorously. I had hoped
to get an edge on preventing future abuse of SMTP error handling by
raising the issue amongst learned and well meaning folks, but instead I
guess wider peer pressure will have to be brought to bear; i.e. there
are apparently still more Exim users yet to be listed on
dsn.rfc-ignorant.org.
--
Greg A. Woods
H:+1 416 218-0098 W:+1 416 489-5852 x122 VE3TCP RoboHack <woods@???>
Planix, Inc. <woods@???> Secrets of the Weird <woods@???>
