I have been receiving the following response to any email I send to any Google mail server (g-suite or gmail) which originates from my virtualmin server.
gmail-smtp-in.l.google.com[2a00:1450:400c:c00::1b] said: 550-5.7.1
[2a02:c205:2010:3724::1 12] Our system has detected that this
550-5.7.1 message is likely unsolicited mail. To reduce the amount of spam
sent 550-5.7.1 to Gmail, this message has been blocked. Please visit
550-5.7.1 https://support.google.com/mail/?p=UnsolicitedMessageError 550
5.7.1 for more information. p9si4077583wmc.109 - gsmtp (in reply to end of
This started after I had an issue with a customers shared server where the customer moved their hosting to Shopify but retained their shared hosting account on my server for email. Somehow one of their email addresses got compromised and thousands of spam emails were being sent via my server. I tried various options to block the spam but eventually I had to move the customer to G-Suite. I then disabled mail delivery on the virtual server and spam emails since stopped.
However my server IP was listed on various blacklists, most of them have since been removed and my server IP reputation has improved significantly although not perfect yet. As a result I have added a second IP address for my server.
I would like to switch to this different IP address for email delivery for all virtual servers. What options do I need to change on Virtualmin / Postfix to do switch of IP address?
Edit: I realize my post may seem as if I have not done any research on this. I have indeed searched other issues but I am yet to find any posts where someone has wanted to add a 2nd IP, configure postfix to use it and modify all virtual servers to send mail using this modified setup. It is possible that just adding the 2nd IP and modifying Postfix is all I need to do, if so, please confirm it is so.
Other similar issues researched:
SPF: checked and all is correct DKIM: checked and all correct rDNS: checked and all correct Spam: IP address not Blacklisted mail-tester.com score: 10/10