[BlueOnyx:17176] Re: TalkTalk bounce

[Michael Stauber]

Hi Colin,

> Further investigation shows that although the sender is relaying off our server the TalkTalk server is picking up his home ADSL IP:
> 
> The original message was received at Sun, 1 Mar 2015 19:23:59 GMT
> from 78-33-150-88.static.enta.net [78.33.150.88]

To clarify: The client has a mailserver on ADSL and is relaying through
your BlueOnyx? Or is he using an email client and SMTP-Auth and sends
email through your BlueOnyx directly?

The distinct difference here: If he relays through you, the email
headers will still show the origin of the email to be his ADSL box and
your BlueOnyx will just be listed as relay in the 2nd line of the
headers. Hence the recipient sees the ADSL box as sender and applies all
the fishiness to it that this ADSL users IP address range might have.

The degree of scrutiny that some SPAM filters apply varies naturally.
Some evaluate just the initial sender. Some just the last relay it came
from. Some evaluate all IPs listed in the header.

Hence: As long as the IP address range of the ADSL sender shows up in
the headers his mails might not go through while using this way.

If he's using an email client and SMTP-Auth (or webmail) and sends from
your server directly, then the mail should go through. Other than that
there is no easy way around this.

-- 
With best regards

Michael Stauber