Anyone running Postfix to self-host email and notice that their home IP address is leaked in the first "Received: from" header? If you haven't noticed, send yourself a message and check if it's happening. If you have noticed, do you care? What have you done to prevent it? If you don't self-host, are you still leaking your home IP? Gmail seems to remove this first header, so in some sense more privacy via Gmail than self-hosting. I've got a temp work-around via header_checks: `apt install postfix-pcre` main.cf: -------- header_checks = /etc/postfix/header_checks.pcre /etc/postfix/header_checks.pcre: -------------------------------- ## WORKS for some messages, not all (this one has ?? delimters - telnet?): /^(Received: from ).*\([0-9\.\-]+cable.teksavvy.com.*\)(.*by .*) from .* (.*)$/AU REPLACE ${1}***ISP name hidden*** ${2} ${3} /^(Received: from ).*\([0-9\.\-]+cable.teksavvy.com.*\)(.*by .*)$/AU REPLACE ${1}***ISP name hidden*** ${2} NOTE: for testing header_checks.pcre, postmap does *not* create a DB and will throw an error if trying to do that like one does with a hash map. Just test by copying an offending header to a script and run it with: postmap -vq "Received: from ..." And the output (of mine) should show: REPLACE Received: from ***ISP name hidden*** ??by mail.bclug.ca (Postfix) with SMTP id 09F5081D15??for <cc@bclug.ca>; Sat, 7 Mar 2026 20:39:30 -0500 (EST) from=<canto_telnet@maow.net> to=<cc@bclug.ca> proto=SMTP helo=<bclug.ca> NOTE: Thunderbird can be configured to set the elho to ehlo.thunderbird.net, which Android client does by default, I believe. https://support.mozilla.org/en-US/kb/thunderbird-smtp-ehlo In the config editor, add or change this key: mail.smtpserver.default.hello_argument to value: ehlo.thunderbird.net