Hi list,
I'm having an issue with my Postfix configuration: Currently I've it set
up so that one authentication SASL login (e.g., m...@foo.com) supports
multiple virtual email addresses (e.g., m...@foo.com but also
f...@foo.com, b...@foo.com).
Once authenticated with m...@foo.com, the envelope sender ("MAIL FROM")
is restricted to only the permissible variants.
However, as I've now painfully found out, when in Thunderbird someone
uses the "Custom From Address" feature, it doesn't change the envelope
sender, but only the actual "From" header field. This means, I have the
following situation:
Auth: m...@foo.com
Envelope from: m...@foo.com
Header 'From': anyth...@goes.com
One of my customers used a gmail address in the header "From", sent an
email to @hotmail.com and now my mailserver is permablocked at Microsoft
for bad reputation.
How can I ensure in the future that the same checks are applied to the
Header "From" field that are also applied to the evelope "From" field?
Thanks,
Johannes
