On Sun, 30 Mar 2003, Jan-Peter Koopmann wrote:
> Hi Greg,
>
> > A server that refuses to accept bounces will not ever accept
> > return mail for any _sender_ address!
>
> I am no SMTP expert but let me add this to the discussion: We turned on
> sender callout verification for a day because I thought it was a great idea.
> Later that day a friend called me and said he could not send me emails
> anymore. I investigated and found out that their Checkpoint firewall
> obviously is either brain-dead or misconfigured. When I tried to deliver an
> e-mail using a real "mail from:" address and her e-mail as "rcpt to:"
> everything worked. Doing the same with "mail from: <>" just resulted in a
> relaying denied right after the "rcpt to:".
>
> I know what you are going to say: Their mailer is not behaving RFC conform
No, their "so called firewall" isn't RFC conform.
An empty envelope sender IS legal and required, to prevent bounce-loops.
> but unfortunately this sort of behaviour is quite commond. Since I am not
It's just heavily broken.
> able to tell exim what to use in "mail from:" I am not able to receive mails
> from such domains.
>
> Is there a config option I am missing?
No, and adding one could be real compley (if it should be made failproof)
