If you are using Postfix with our Outbound filtering system, and you need to forward your incoming messages, you may need to enable Sender Rewriting Scheme (SRS - http://www.openspf.org/SRS) for these forwards. This will cause the messages being forwarded to use your domain name, so our outbound filter will allow the messages to pass.

• Ensure you have PCRE support installed for Postfix:
  
  sudo apt-install postfix-pcre

• Create and edit a file which will contain the regular expression for changing the sender address:
  
  sudo vi /etc/postfix/canonical

• Add this line to the new file, but replace yourDomain.com with your actual domain (this must be either subscribed or aliased on your SpamHero account):
  
  /^.*@(?!yourDomain\.com).*$/ bounce@yourDomain.com

• Map the new changes into Postfix compatibility:
  
  postmap pcre:/etc/postfix/canonical

• Add this to your /etc/postfix/main.cf file:
  
  canonical_maps = pcre:/etc/postfix/canonical
  canonical_classes = envelope_sender

• Reload the Postfix configuration:
  
  postfix reload

This will set the Return-Path address for your outbound mail to bounce@[yourDomain.com], which will be accepted by SpamHero.