Hi there I noticed that some user sends an email from a hotmail account to to a forwarding address entry on the server. The server then forwards that email to multiple recipients. This all works fine, except in gmail such emails land in the spam folder. The reason is that Microsoft's SPF doesn't allow my server to send those emails: Code: Received-SPF: softfail (google.com: domain of transitioning ...@hotmail.com does not designate 18.104.22.168 as permitted sender) client-ip=22.214.171.124; How can this be fixed? SRS seems to be a way: http://www.openspf.org/SRS / https://www.mind-it.info/2014/02/22/forward-postfix-spf-srs/ but I'm not really sure how that works together with the perfect setups for ISPC. Any input?