Daniele Nicolodi:
> Currently I'm able to send emails to my address @gmail.com from the
> email address I'm currently using without having them classified as
> spam, but not from any email address having a different local part. I
> believe this is because my @grinta.net email address is white listed for
> my @gmail.com email address.
>
> Of course, Google does not care about the issue.
Maybe this helps:
Go to your Mail settings and Accounts tab and add the address
you are forwarding from to 'Send mail as'. This is a new feature
from user requests, where Gmail will detect that you forwarded
from that account and help prevent displaying a phishing warning.
https://support.google.com/a/answer/175365?hl=en
Wietse