Mailscanner, forwarding and SPF

[Antony Stone]

On Tuesday 21 February 2017 at 13:15:51, Nerk Nerk wrote:

> Thank you for your answers.
> 
> The problem is, that the people that use my filters, don't own the server
> that their email is hosted on. So they can't always decide to turn
> something off.

So, maybe they should consider owning their own server, or having a fully-
hosted email service (not just filtering) from you?


Further information on how the mail flow works (see my questions below) would 
be helpful to us if you want some suggestions on how to set up a workaround, 
if the customer isn't prepared or able to make the ideal changes.

> 2017-02-21 12:56 GMT+01:00 Antony Stone:
> > On Tuesday 21 February 2017 at 12:48:18, Nerk Nerk wrote:
> > > Dear MailScanner-fanatics,
> > > 
> > > Currently I am facing some issues using MailScanner. Mostly, when the
> > > following situation is current:
> > > 
> > > - Some domain using SPF, for example Paypal, sends a mail to a domain
> > > that I filter for
> > 
> > So, you are the destination of the MX records...
> > 
> > > - The domain is filtered through Mailscanner
> > > - The e-mail is forwarded to the destination
> > 
> > How does that happen?
> > 
> > > - The destination server is not under my control. They do SPF checking
> > > and reject the mail because the sending domain does not list my
> > > mailscanner IP as a valid sender
> > > 
> > > Ofcourse I have thought of some solutions:
> > > 1- They need to whitelist the IP of my mailscanner
> > 
> > That would be good, considering that they've bought (?) a filtering
> > service from you, and expect mail to pass through your servers on the
> > way to theirs.
> > 
> > > 2- They need to turn off the SPF checks at the destination
> > 
> > Do they receive any direct (ie: not filtered through your servers) email?
> > 
> > > Both solutions however, require actions from a hosting party that I
> > > don't know and that is probably not willing.
> > 
> > So, why have they pointed their MX records at your server, if they're not
> > wiling to adjust their server to match this?
> > 
> > > A third option:
> > > 3- I need to rewrite the sending domain somehow
> > 
> > Yes, like many mailing lists do.
> > 
> > > Has anyone else come across this problem? How did you solve it?
> > > 
> > > I am really wondering what solution commercial spam filtering services,
> > > such as SpamExperts for example, are using.
> > 
> > I can't speak for them.
> > 
> > 
> > Antony.

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