I am not sure that I understand. My server is using a static(Public) IP address. It is outside of the NAT router. My workstation is inside the NAT router. When I send an email, the first header that gets inserted is:
Received: from GERDES (unknown [220.127.116.11]) by cronos.homenetnw.com (Postfix) with ESMTP id 49E92474472 for <email@example.com>; Mon, 6 Mar 2006 16:09:53 -0800 (PST)
The NAT ip is 18.104.22.168. If I remove or replace that IP, won't that stop spamassassin from checking that IP for blacklisting?
I work for the ISP whose NAT router is always being blacklisted. Should I instead restrict port 25 access so that I won't get that IP address blacklisted anymore. I'm confused about how to proceed. Any help you can provide would be greatly appreciated.